Let's recall that the formula of the perimeter of an equilateral triangle is:
Side + Side + Side
3Side
3 * 3x = 9x
And now, let's calculate the perimeter of the square:
Side + Side + Side + Side
4Side
4 (x + 5)
4x + 20
Let's solve for x, as follows:
9x = 4x + 20
9x - 4x = 20
5x = 20
Dividing by 5:
5x/5 = 20/5
x = 4
Ash, now you can easily find the length of the sides of the square and triangle.
