Answer:
2 sqrt(5) =x
Explanation:
We can use the Pythagorean theorem since this is a right triangle
a^2 + b^2 = c^2
2^2 +4^2 = x^2
4+16 = x^2
20 = x^2
Take the square root of each side
sqrt(20) = sqrt(x^2)
sqrt(4*5) = x
sqrt(4) sqrt(5) =x
2 sqrt(5) =x