Question

the edge of an equilateral triangle has a size of x cm. the side of a square has an edge of x - 5cm. what value of x gives both shapes the same perimeter?

Answer 1

The perimeter of the triangle is 3x. The perimeter of the square is 4(x-5). When the two perimeters are equal 3x=4(x-5); 3x=4x-20; 20=4x-3x=x. Therefore x=20cm. 3*20=4*15=60cm.