Question 656791
Let 'l' be the length of the rectangle and 'w' be the width of the rectangle 
Given:l=3w and Perimeter,P=32 cm
 P= 2*(l+w)
Substitute the given value for l
 32 = 2(3w+w)
 32/2 = 4w
 4w = 16
 w= 16/4
 w= 4
l= 3*w
l= 3*4
l= 12
Length of a rectangle is 12cm and width is 4cm