Answer:
4sqrt(3)
Explanation:
If the triangle is equilateral, the hypotenuse is 2x
We can use the Pythagorean theorem
a^2 + b^2 = c^2 where a and b are the legs and c is the hypotenuse
x^2 + 12^2 = (2x)^2
x^2 + 144 = 4x^2
144 = 4x^2 -x^2
144 = 3x^2
48 = x^2
Taking the square root of each side
sqrt(48) = sqrt(x^2)
sqrt(16*3) = x
4 sqrt(3) =x