Find the width of the frame.

Question

A rectangular picture measures 3m by 4m has a frame of uniform width. The area of the picture is half the area of the frame. Find the width of the frame.

Answer 1

12 = (1/2) area of the frame

the frame area = ((3+x)(4+x) - 12) divided by 2 = picture area = 3x4 = 12

x^2 +7x = 24

x^2 +7x -24 = 0

x = -7/2 + .5sqr(49+96) = -3.5+.5sqr145 = about 6-3.5 =about 2.5 m = frame width