Answer:
D. 8.7
Step-by-step explanation:
In order to say anything about the length of b, we must assume the triangle is a right triangle. Then the Pythagorean theorem applies, and we have ...
c² = a² +b²
b² = c² -a² . . . . . subtract a²
b = √(c² -a²) . . . . . . take the square root
b = √(10² -5²) = √(100 -25) = √75
b ≈ 8.7
