Answer:
8 meters
Explanation:
Let side of square be "x"
and
Let side of equilateral triangle (triangle with all equal sides) be "y"
we know perimeter is the "sum of all the sides".
Now,
square's side is 10 longer than triangle's side, so we can write:
x = 10 + y
The perimeter of square is x + x + x + x = 4x
The perimeter of equilateral triangle is y + y + y = 3y
Now, perimeter of square is 3 times perimeter of triangle, so we can write:
4x = 3(3y)
4x = 9y
Now we replace this with 1st equation and solve for y:
4x = 9y
4(10 + y) = 9y
40 + 4y = 9y
40 = 5y
y = 40/5 = 8
The length of each side of triangle is 8 meters