You need to buy a new cover for your pool. the pool is in the shape of a trapezoid. the cost of the cover is $0.79 per square foot. use the diagram to find the total cost of the pool cover.

First we have to work out the area of the trapezoid using the formula;
1/2 (a+b) h

The height is 16ft, and a = 24ft, and b = 15ft
Put this into the formula

1/2 (24 + 15) 16
1/2 39 * 16
39 * 8  (you can halve the 16)
= 312 ft squared

Now we simply multiply the area by the cost per square foot to get our answer.

312 * 0.79 = $246.48