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Area, SM-Bank 118

Calculate the area of a circle with a diameter of 37.4 millimetres. Give your answer correct to one decimal place.   (2 marks)

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\(1098.6\ \text{mm}^2\ (1 \text{ d.p.})\)

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\(\text{Diameter}=37.4\ \text{mm}\)

\(\therefore\ \text{Radius}=18.7\ \text{mm}\)

\(\text{Area}\) \(=\pi r^2\)
  \(=\pi\times 18.7^2\)
  \(=1098.583\dots\)
  \(=1098.6\ \text{mm}^2\ (\text{1 d.p.})\)

Area, SM-Bank 117

Calculate the area of a circle with a radius of 72.3 centimetres. Give your answer correct to one decimal place.   (2 marks)

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\(16\ 422.0\ \text{cm}^2\ (1\ \text{d.p.})\)

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\(\text{Area}\) \(=\pi r^2\)
  \(=\pi\times 72.3^2\)
  \(=16\ 422.015\dots\)
  \(=16\ 422.0\ \text{cm}^2\ (1 \text{ d.p.})\)

Area, SM-Bank 116

Calculate the area of a circle with a radius of 20 metres. Give your answer as an exact value in term of \(\pi\).   (2 marks)

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\(400\pi\ \text{m}^2\)

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\(\text{Area}\) \(=\pi r^2\)
  \(=\pi\times 20^2\)
  \(=400\pi\ \text{m}^2\)

Area, SM-Bank 108

Calculate the area of the following circle, giving your answer as an exact value in terms of \(\pi\).   (2 marks)
 

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\(25\pi\ \text{m}^2\)

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\(\text{Diameter}=10\ \text{m}\)

\(\therefore\ \text{Radius}=5\ \text{m}\)

\(\text{Area}\) \(=\pi r^2\)
  \(=\pi\times 5^2\)
  \(=25\pi\ \text{m}^2\)

Area, SM-Bank 107

Calculate the area of the following circle, correct to one decimal place.  (2 marks)
 

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\(422.7\ \text{cm}^2\ (1\ \text{d.p.})\)

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\(\text{Diameter}=23.2\ \text{cm}\)

\(\therefore\ \text{Radius}=11.6\ \text{cm}\)

\(\text{Area}\) \(=\pi r^2\)
  \(=\pi\times 11.6^2\)
  \(=422.7327\dots\)
  \(\approx 422.7\ \text{cm}^2\ (1\ \text{d.p.})\)

Area, SM-Bank 106

Calculate the area of the following circle, correct to one decimal place.   (2 marks)
 

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\(50.3\ \text{m}^2\ (1\ \text{d.p.})\)

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\(\text{Area}\) \(=\pi r^2\)
  \(=\pi\times 4^2\)
  \(=50.2654\dots\)
  \(\approx 50.3\ \text{m}^2\ (1\ \text{d.p.})\)

Area, SM-Bank 105

Calculate the area of the following circle, correct to one decimal place.  (2 marks)
 

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\(514.7\ \text{cm}^2\ (1\ \text{d.p.})\)

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\(\text{Area}\) \(=\pi r^2\)
  \(=\pi\times 12.8^2\)
  \(=514.7185\dots\)
  \(\approx 514.7\ \text{cm}^2\ (1\ \text{d.p.})\)

Area, SM-Bank 034

The radius of a circle is 6.5 centimetres.

A square has the same area as this circle.

Calculate the side length of the square, in centimetres correct to one decimal place.   (3 marks)

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\(11.5\ \text{cm}\)

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\(\text{Area of circle}\) \(=\pi r^2\)
  \(=\pi\times 6.5^2\)
  \(= 132.73\dots\ \text{cm}^2\)

 
\(\text{Area of square}\ =s^2=\ \text{Area of circle}\)

\(s^2\) \(= 132.73\dots\)
\(s\) \(=\sqrt{132.73\dots}\)
  \(= 11.5\ \text{cm (1 d.p.)}\)