The wall is a rectangle, so by the pythagorean theorem, the diagonal squared minus the height squared equals the width squared. This gives a width of 42.80 feet. The area of the wall is width (42.80 ft) x height (8.3 ft), equal to 355.26 square ft. The can covers 21.5 square feet, so John needs 16.52 cans to cover the wall. As he can't buy half a can, John should purchase 17 cans of spraypaint.The wall is a rectangle, so by the pythagorean theorem, the diagonal squared minus the height squared equals the width squared. This gives a width of 42.80 feet. The area of the wall is width (42.80 ft) x height (8.3 ft), equal to 355.26 square ft. The can covers 21.5 square feet, so John needs 16.52 cans to cover the wall. As he can't buy half a can, John should purchase 17 cans of spraypaint.
