Answer:
D 5sqrt(3)
Explanation:
We can use the Pythagorean theorem to solve since the altitude is perpendicular to the base
a^2+b^2 = c^2
5^2 + a^2 = 10^2
25+a^2 = 100
a^2 =100-25
a^2 = 75
Taking the square root of each side
a = sqrt(75)
a = sqrt(25)sqrt(3)
a = 5sqrt(3)