Test Index

BECE Mathematics 2015 Paper

Question : 26

Total: 40

\pi = \frac{22}{7}

Solution:

Concept:

Use the circumference formula to find the radius, then use the radius to find the area of the circle.

Explanation:

Circumference of a circle is given by

C = 2\pi r

Here,

C = 440 \text{ m}

and

\pi = \frac{22}{7}

So,

440 = 2 \times \frac{22}{7} \times r

Simplify:

440 = \frac{44}{7} \times r

Multiply both sides by

7

440 \times 7 = 44r

Divide both sides by

44

r = \frac{440 \times 7}{44} = 10 \times 7 = 70 \text{ m}

Now, area of a circle is

A = \pi r^2

Substitute

r = 70 \text{ m}

and

\pi = \frac{22}{7}

A = \frac{22}{7} \times 70^2 = \frac{22}{7} \times 70 \times 70

Since

\frac{70}{7} = 10

, we get

A = 22 \times 10 \times 70 = 15,400 \text{ m}^2

Answer:

The area of the circle is

15,400 \text{ m}^2

Correct option: B.

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