The perimeter of a rectangle is 46cm. What are the dimensions if the length is 4 less than twice the width?

we can give the width and length variables. lets call them x and y respectively. we know that y=2x-4

the perimeter is equal to 2x + 2y or 2(x + y). 

the perimeter in terms of x is 2(x + 2x-4) = 2(3x-4) = 6x-8

6x-8=46

6x=54

x=9cm

if y=2x-4, then y=9*2 - 4=18-4=14.

y=14cm

 

the width is 9cm and the length is 14cm