Use the arc length formula below to calculate the arc length of the sector, correct to one decimal place. (2 marks)
\(l=\dfrac{\theta}{360}\times 2\pi r\)
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Use the arc length formula below to calculate the arc length of the sector, correct to one decimal place. (2 marks)
\(l=\dfrac{\theta}{360}\times 2\pi r\)
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\(25.0\ \text{m (1.d.p.)}\)
| \(l\) | \(=\dfrac{\theta}{360}\times 2\pi r\) |
| \(=\dfrac{135}{360}\times 2\pi \times 10.6\) | |
| \(=24.9756\dots\) | |
| \(=25.0\ \text{m (1.d.p.)}\) |
Use the arc length formula below to calculate the arc length of the sector, correct to one decimal place. (2 marks)
\(l=\dfrac{\theta}{360}\times 2\pi r\)
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\(4.2\ \text{cm (1.d.p.)}\)
| \(l\) | \(=\dfrac{\theta}{360}\times 2\pi r\) |
| \(=\dfrac{30}{360}\times 2\pi \times 8\) | |
| \(=4.1887\dots\) | |
| \(=4.2\ \text{cm (1.d.p.)}\) |
Evan rides his bike around a circular track with a radius of 150 metres.
He rides the track 5 days a week and wants to have ridden 230 kilometres by the end of the week.
What is the minimum number of laps, to the nearest whole lap, he must complete each day to achieve his target? (3 marks)
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\(49\ \text{laps}\)
\(\text{Total Distance}=230\ \text{km}=230\ 000\ \text{m}\)
| \(\text{Total laps}\) | \(=\dfrac{230\ 000}{C}\) |
| \(=\dfrac{230\ 000}{300\pi}\) | |
| \(=244.037\dots\) |
| \(\text{Laps per day:}\) | \(=\dfrac{244.037\dots}{5}\) |
| \(=48.807\dots\) | |
| \(\approx 49\ \text{laps}\) |
\(\therefore\ \text{Evan needs to ride }49\ \text{laps per day to achieve his goal}.\)
\(\Big[\text{Check: }49\times 5\times 300\pi=230\ 907.06\ \text{m}=230.907\ \text{km}\Big]\)
A car tyre has a circumference of 120 cm.
Which of these is closest to the radius of the tyre?
\(B\)
| \(C\) | \(=2 \pi r\) |
| \(120\) | \(=2\times \pi\times r\) |
| \(r\) | \(=\dfrac{120}{2 \pi}\) |
| \(=19.098\dots\) | |
| \(\approx 19.1\ \text{cm}\) |
\(\Rightarrow B\)
A yoyo at the end of a string moves through a quarter circle arc, as shown below.
The string is 70 cm long.
The curved distance the yoyo has travelled is closest to
\(D\)
| \(\text{Distance}\) | \(=\dfrac{1}{4}\times 2\pi r\) |
| \(=\dfrac{1}{4}\times 2\pi 70\) | |
| \(= 109.9557\dots\) | |
| \(\approx 110\ \text{cm}\) |
\(\Rightarrow D\)
Guerra slings a fire torch in a circle at the end of a 3 metre rope.
How far has the fire torch travelled after completing 15 circles?
Give your answer correct to the nearest whole number. (2 marks)
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\(283\ \text{metres (nearest whole number)}\)
\(\text{Distance travelled in 1 revolution:}\)
| \(C\) | \(=2\pi r\) |
| \(=2\times \pi\times 3\) | |
| \(= 18.8495\dots\) |
\(\therefore\ \text{Distance travelled in }15\ \text{revolutions:}\)
\(=15\times 18.8495\dots\)
\(= 282.7433\dots\)
\(=283\ \text{metres (nearest whole number)}\)
A wheel on a bicycle has a diameter of 530 mm.
The wheel turns 12 times.
Approximately how many metres has the bicycle travelled?
\(B\)
\(\text{Diameter}=530\ \text{mm}=0.530\ \text{m}\)
| \(\therefore\ \text{Distance}\) | \(=12\times \text{circumference}\) |
| \(=12\times \pi d\) | |
| \(=12\times \pi\times 0.530\) | |
| \(=19.9805\dots\) | |
| \(=20\ \text{m (nearest m)}\) |
\(\Rightarrow B\)
Percy has a large shower head which has a diameter of 25.5 centimetres.
What is the circumference of the shower head in centimetres, correct to one decimal place? (2 marks)
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\(80.1\ \text{cm}\ (1\ \text{d.p.})\)
| \(C\) | \(=\pi d\) |
| \(=\pi\times 25.5\) | |
| \(=80.110\dots\) | |
| \(=80.1\ \text{cm}\ (1\ \text{d.p.})\) |
Calculate the radius of a circle with a circumference of 870 metres, correct to the nearest ten metres. (2 marks)
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\(140\ \text{m}\ (\text{nearest ten})\)
| \(C\) | \(=2\pi r\) |
| \(870\) | \(=2\pi r\) |
| \(r\) | \(=\dfrac{870}{2\pi}\) |
| \(=138.4648\dots\) | |
| \(=140\ \text{m}\ (\text{nearest ten})\) |
Calculate the radius of a circle with a circumference of 324 centimetres, correct to 2 decimal places. (2 marks)
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\(51.57\ \text{cm}\ (2\ \text{d.p.})\)
| \(C\) | \(=2\pi r\) |
| \(324\) | \(=2\pi r\) |
| \(r\) | \(=\dfrac{324}{2\pi}\) |
| \(=51.5662\dots\) | |
| \(=51.57\ \text{cm}\ (2\ \text{d.p.})\) |
Calculate the diameter of a circle with a circumference of 109.8 metres, correct to 2 decimal places. (2 marks)
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\(34.95\ \text{m}\ (2\ \text{d.p.})\)
| \(C\) | \(=\pi d\) |
| \(109.8\) | \(=\pi d\) |
| \(d\) | \(=\dfrac{109.8}{\pi}\) |
| \(=34.9504\dots\) | |
| \(=34.95\ \text{m}\ (2\ \text{d.p.})\) |
Calculate the diameter of a circle with a circumference of 24 centimetres, correct to 1 decimal place. (2 marks)
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\(7.6\ \text{cm}\ (1\ \text{d.p.})\)
| \(C\) | \(=\pi d\) |
| \(24\) | \(=\pi d\) |
| \(d\) | \(=\dfrac{24}{\pi}\) |
| \(=7.639\dots\) | |
| \(=7.6\ \text{cm}\ (1\ \text{d.p.})\) |
Calculate the circumference of a circle with a radius of 1012 centimetres, correct to the nearest hundred. (2 marks)
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\(6400\ \text{cm}\ (\text{nearest hundred})\)
| \(C\) | \(=2\pi r\) |
| \(=2\pi\times 1012\) | |
| \(=6358.5835\dots\) | |
| \(=6400\ \text{cm}\ (\text{nearest hundred})\) |
Calculate the circumference of a circle with a radius of 453 kilometres, correct to the nearest whole number. (2 marks)
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\(2846\ \text{km}\ (\text{nearest whole number})\)
| \(C\) | \(=2\pi r\) |
| \(=2\pi\times 453\) | |
| \(=2846.2829\dots\) | |
| \(=2846\ \text{km}\ (\text{nearest whole number})\) |
Calculate the circumference of a circle with a diameter of 24.6 millimetres, correct to 0ne decimal place. (2 marks)
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\(77.3\ \text{mm}\ \ (1\ \text{d.p.})\)
| \(C\) | \(=\pi d\) |
| \(=\pi\times 24.6\) | |
| \(=77.2831\dots\) | |
| \(=77.3\ \text{mm}\ \ (1\ \text{d.p.})\) |
Calculate the circumference of a circle with a diameter of 35 centimetres, correct to two decimal places. (2 marks)
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\(109.96\ \text{cm}\ \ (2\ \text{d.p.})\)
| \(C\) | \(=\pi d\) |
| \(=\pi\times 35\) | |
| \(=109.9557\dots\) | |
| \(=109.96\ \text{cm}\ \ (2\ \text{d.p.})\) |
Calculate the circumference of the circle below correct to two decimal places. (2 marks)
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\(653.45\ \text{cm}\ \ (2\ \text{d.p.})\)
| \(C\) | \(=2\pi r\) |
| \(=2\pi\times 104\) | |
| \(=653.4512\dots\) | |
| \(=653.45\ \text{cm}\ \ (2\ \text{d.p.})\) |
Calculate the circumference of the circle below correct to one decimal place. (2 marks)
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\(44.0\ \text{cm}\ \ (1\ \text{d.p.})\)
| \(C\) | \(=2\pi r\) |
| \(=2\pi\times 7\) | |
| \(=43.9822\dots\) | |
| \(=44.0\ \text{cm}\ \ (1\ \text{d.p.})\) |
Calculate the circumference of the circle below correct to one decimal place. (2 marks)
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\(38.3\ \text{m}\ \ (1\ \text{d.p.})\)
| \(C\) | \(=\pi d\) |
| \(=\pi\times 12.2\) | |
| \(=38.3274\dots\) | |
| \(=38.3\ \text{m}\ \ (1\ \text{d.p.})\) |
Calculate the circumference of the circle below correct to two decimal places. (2 marks)
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\(15.71\ \text{m}\ \ (2\ \text{d.p.})\)
| \(C\) | \(=\pi d\) |
| \(=\pi\times 5\) | |
| \(=15.7079\dots\) | |
| \(=15.71\ \text{m}\ \ (2\ \text{d.p.})\) |
Use a calculator to evaluate \(2\large\pi r\) correct to 1 decimal place, when \(\large r\)\(=2.1\). (2 marks)
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\(13.2\ (1\ \text{d.p.})\)
| \(2\pi r\) | \(=2\times \pi\times 2.1\) |
| \(=13.194\dots\) | |
| \(=13.2\ (1\ \text{d.p.})\) |
Evaluate \(5\large\pi\) using a calculator, giving your answer correct to 2 decimal places. (1 mark)
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\(15.71\ (2\ \text{d.p.})\)
| \(5\pi\) | \(=15.7079\dots\) |
| \(=15.71\ (2\ \text{d.p.})\) |
Which of the following is the definition of the circumference of a circle?
\(C\)
Which of the following is the definition of the radius of a circle?
\(D\)
Which of the following is the definition of the diameter of a circle?
\(A\)
Which of the following is the definition of an arc?
\(B\)
What fraction of a circle is indicated in the diagram below? (1 mark)
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\(\dfrac{1}{12}\)
| \(\text{Angle}\) | \(=\dfrac{\theta}{360}\) |
| \(=\dfrac{30}{360}\) | |
| \(=\dfrac{1}{12}\) |
What fraction of a circle is indicated in the diagram below? (1 mark)
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\(\dfrac{1}{4}\)
| \(\text{Angle}\) | \(=\dfrac{\theta}{360}\) |
| \(=\dfrac{90}{360}\) | |
| \(=\dfrac{1}{4}\) |
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What fraction of a circle is indicated in the diagram below? (1 mark)
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\(\dfrac{3}{8}\)
| \(\text{Angle}\) | \(=\dfrac{\theta}{360}\) |
| \(=\dfrac{135}{360}\) | |
| \(=\dfrac{3}{8}\) |
What fraction of a circle is indicated in the diagram below? (1 mark)
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\(\dfrac{1}{8}\)
| \(\text{Angle}\) | \(=\dfrac{\theta}{360}\) |
| \(=\dfrac{45}{360}\) | |
| \(=\dfrac{1}{8}\) |
If the diameter of a circle is 16.2 millimetres, what is the length of its radius? (1 mark)
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\(8.1\ \text{mm}\)
| \(\text{Radius}\) | \(=\dfrac{\text{diameter}}{2}\) |
| \(=\dfrac{16.2}{2}\) | |
| \(=8.1 \text{mm}\) |
If the radius of a circle is 24 centimetres, what is the length of its diameter? (1 mark)
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\(48\ \text{cm}\)
| \(\text{Diameter}\) | \(=2\times\text{radius}\) |
| \(=2\times 24\) | |
| \(=48\ \text{cm}\) |
Name the circle parts indicated in the drawing below. (2 marks)
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a. \(\text{Secant}\)
b. \(\text{Quadrant}\)
a. \(\text{Secant}\)
b. \(\text{Quadrant}\)
Name the circle parts indicated in the drawing below. (2 marks)
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a. \(\text{Major segment}\)
b. \(\text{Tangent}\)
a. \(\text{Major segment}\)
b. \(\text{Tangent}\)
Name the circle parts indicated in the drawing below. (2 marks)
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a. \(\text{Centre}\)
b. \(\text{Arc}\)
a. \(\text{Centre}\)
b. \(\text{Arc}\)
Name the circle parts indicated in the drawing below. (2 marks)
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a. \(\text{Semicircle}\)
b. \(\text{Minor segment}\)
a. \(\text{Semicircle}\)
b. \(\text{Minor segment}\)
Name the circle parts indicated in the drawing below. (2 marks)
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a. \(\text{Radius}\)
b. \(\text{Sector}\)
a. \(\text{Radius}\)
b. \(\text{Sector}\)
Name the circle parts indicated in the drawing below. (2 marks)
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a. \(\text{Diameter}\)
b. \(\text{Chord}\)
a. \(\text{Diameter}\)
b. \(\text{Chord}\)
An isosceles triangle has a base of length 4 centimetres and a perimeter of 20 centimetres.
Find the length of the equal sides. (2 marks)
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\(8\ \text{cm}\)
\(\text{Let the length of the equal sides be}\ x\)
| \(\text{Then,}\ \ 2\times x+4\) | \(=20\) |
| \(2x\) | \(=20-4\) |
| \(2x\) | \(=16\) |
| \(x\) | \(=8\) |
\(\therefore\ \text{The equal sides are of length }8\ \text{cm}\)
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a.
b. \(54\ \text{mm}\)
a.
b. \(\text{Perimeter}\)
\(=13+2\times 9+4+2\times 5+3+6\)
\(=54\ \text{mm}\)
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a.
b. \(52\ \text{cm}\)
a.
b. \(\text{Perimeter}\)
\(=12+14+5+10+7+4\)
\(=52\ \text{cm}\)
A farmer uses the river bordering his property and fencing to create a large grazing paddock for his horses, as shown in the diagram below.
The fencing has 4-strand wiring which is also shown below.
Given that fencing is not required on the river boundary, how many kilometres of wire will be required to fence the rest of the paddock? (2 marks)
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\(5.6\ \text{km}\)
\(\text{Wire needed}\)
\(=4\times(700+200+300+1100+200+200+1200)\)
\(=4\times 3900\)
\(=15\ 600\ \text{m}=15.6\ \text{km}\)
Jill cut a piece of binding in half.
She then placed one half on top of the other half, as shown below.
What is the perimeter of the newly formed shape in millimetres? (2 marks)
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\(1600\ \text{mm}\)
\(\text{Calculating the perimeter clockwise from top right:}\)
\(\text{Perimeter}\)
\(=18+2\times 382 +18+2\times 400\)
\(=1600\ \text{mm}\)