Question

A small painting has an area of 400 cm^2. The length is 4 more than twice the width. Find the dimensions of the pool. Solve by completing the square. Round answers to the nearest tenth.

Answer 1

A = l*w
l = 2w + 4
400 = (2w + 4)*w
0 = 2w^2 + 4w - 400

Then use the quadratic equation where a=2, b=4, and c=-400.

w = 13.2
l = 30.4