secondary (math 20)

Question : The community of melfort is planning to build a circular wading pool in the park. The pool will cover an area of 1000m2. The building committee has decided to put a 5m cement pad around it. How much additional area will the cement pad take up? (remember A=pi r squared)

Hi Patrick,

A diagram here helps a lot.

The pool has an unknown radius of p meters and hence the radius to the outside edge of the cement is p + 5 meters.

Since the area of a circle of radius r is  r2, the area of the cement pad is

(p + 5)2 - p2 All that remains is to find p and then perform the calculation.

Since the area of the pool is 1000 m2 we know that

1000 = p2 Thus

I hope this helps,
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