Rectangle a has one side which is 6cm long and the other is (x+2)cm long. rectangle y has sides of length (2x+1) and 3cm, if the perimeters are the same, calculate the value of x and hence, the lengths of the sides of the rectangles.

Hello, 

Rectangle A:           6cm                  (x+2)cm
Rectangle B:           3cm                  (2x+1)cm

The formula for the perimeter of a rectangle is: P=2(base+height)

Then:



But we know that the perimeters are the same, so:



With the answer of A, we realize that this figure is actually a square.

X=3 and y=4 is the answer

The right answer is option d.