The cylinder shown below has a diameter of 18 centimetres and a length of 45 centimetres.
Find the volume of the cylinder, giving your answer to the nearest cubic centimetre. (2 marks)
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The cylinder shown below has a diameter of 18 centimetres and a length of 45 centimetres.
Find the volume of the cylinder, giving your answer to the nearest cubic centimetre. (2 marks)
`11\ 451\ text(cm)^3`
`text(Volume)` | `= pi r^2 h` |
`= pi xx 9^2 xx 45` | |
`= 11\ 451.10…` | |
`= 11\ 451\ text(cm)^3\ \ text{(nearest cm}^3 text{)}` |
A cylindrical water tank has a radius of 9 metres and a capacity of 1.26 megalitres.
What is the height of the water tank? Give your answer in metres, correct to two decimal places. (3 marks)
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`4.95\ text{m}`
`text{Converting megalitres to m³ (using 1 m³ = 1000 L):}`
`1.26\ text(ML)` | `= (1.26 xx 10^6)/(10^3)` |
`= 1.26 xx 10^3\ text(m)^3` | |
`= 1260\ text(m)^3` |
`V` | `= pir^2h` |
`1260` | `= pi xx 9^2 xx h` |
`h` | `= 1260/(pi xx 9^2)` |
`= 4.951…` | |
`= 4.95\ text{m (2 d.p.)}` |
A company makes large marshmallows. They are in the shape of a cylinder with diameter 5 cm and height 3 cm, as shown in the diagram.
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A cake is to be made by stacking 24 of these large marshmallows and filling the gaps between them with chocolate. The diagrams show the cake and its top view. The shading shows the gaps to be filled with chocolate.
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i. | `V` | `= pir^2h` |
`= pi xx 2.5^2 xx 3` | ||
`= 58.904…` | ||
`= 58.9\ text{cm³ (1 d.p.)}` |
ii. |
`text(Volume of rectangle)`
`= 15 xx 10 xx 6`
`= 900\ text(cm)^3`
`text(Volume of marshmallows in rectangle)`
`= 6 xx 2 xx 58.9`
`= 706.8\ text(cm)^3`
`:.\ text(Volume of chocolate)`
`= 900-706.8`
`= 193.2`
`= 193\ text{cm}^3 \ text{(nearest cm}^3 text{)}`
A clay brick is made in the shape of a rectangular prism with dimensions as shown.
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Three identical cylindrical holes are made through the brick as shown. Each hole has a radius of 1.4 cm.
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i. | `V` | `= l × b × h` |
`= 21 × 8 × 9` | ||
`= 1512\ text(cm)^3` |
ii. `text(Volume of each hole)`
`= pir^2h`
`= pi × 1.4^2 × 8`
`= 49.260…\ text(cm)^3`
`:.\ text(Volume of clay still in brick)`
`= 1512 − (3 × 49.260…)`
`= 1364.219…`
`= 1364\ text{cm}^3\ text{(nearest whole)}`
iii. `text(Percentage of clay removed)`
`= ((3 × 49.260…))/1512 × 100`
`= 9.773…`
`= 9.8 text{% (1 d.p.)}`
The base of a water tank is in the shape of a rectangle with a semicircle at each end, as shown.
The tank is 1400 mm long, 560 mm wide, and has a height of 810 mm.
What is the capacity of the tank, to the nearest litre? (4 marks)
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`581\ text(L)`
`V = Ah`
`text(Finding Area of base)`
`text(Semi-circles have radius 280 mm) = 0.28\ text(m)`
`:.\ text(Area of 2 semicircles)`
`=2 xx 1/2 xx pi r^2`
`= pi xx (0.28)^2`
`= 0.2463…\ text(m)^2`
`text(Area of rectangle)`
`= l xx b`
`= (1.4-2 xx 0.28) xx 0.56`
`= 0.4704\ text(m)^2`
`:.\ text(Volume)` | `= Ah` |
`= (0.2463… + 0.4704) xx 0.810` | |
`= 0.580527…\ text(m)^3` | |
`= 580.527…\ text(L)\ \ text{(using 1m³} = 1000\ text{L)}` | |
`= 581\ text(L)\ text{(nearest L)}` |