Question

The perimeter of a cross section of a piece of lumber is 16 1/2in. The length is twice the width. Find the actual dimensions of the cross section of this piece of lumber.
The width is__ in.

Answer 1

the perimeter of the cross section is 16.5 inches.
the perimeter of the cross section is 2*L plus 2*W where L is the length of the cross section and W is the width of the cross section.
since L = 2*W, the perimeter becomes 4*W plus 2*W = 6*W.

16.5 / 6 = 2.75 inches.
W = 2.75 inches.
L = 5.5 inches.
P = 2*L + 2*W = 2*5.5 + 2*2.75 = 11 + 5.5 = 16.5