Find Perimeter

Question

A square and an equilateral triangle have a combined perimeter of 101 inches. The side length of the triangle is 8 inches less than twice the side length of the square. What is the perimeter of the square?

Answer 1

Let s = side length of the equilateral triangle;  

Let x be the square's side length.

 

If the side length of the triangle s = 2x - 8, then  x = ½(s+8)

 

The combined PERIMETER is therefore 4x + 3s = 101  in.

 

Solve for x after substituting in the above for s.

 

Once you have solved for x,  the perimeter of the square, 4x, can be found.

 

Note: assumes the square and the equilateral triangle are not conjoined in any way.