Answer:
x = 6 units
Explanation:
To solve this you can use Pythagorean Theorem;
A² + B² = C²
Where A and B are the legs of the triangle and C is the hypotenuse which always the diagonal line
So now that we know;
A = 8
B = x
C = 10
We can substitute and solve;
A² + B² = C²
(8)² + (x)² = (10)²
64 + (x)² = 100
(x)² = 36
x = √36
x = 6
Hope this helps!