Answer:
x = 6
Explanation:
The triangle is a right triangle, as denoted by the red square at the bottom, we can use the Pythagorean Theorem to figure out the second side (since we are given the other side and the hypotenuse).
a² + b² = c²
(8)² + b² = (10)²
64 + b² = 100
b² = 100 - 64 = 36
b = ±
b = ± 6
But we know that distance is always positive, so
b = 6
I have used b in place of x if you are confused about the variable usage.