b = 6 (option D)
Step-by-step explanation:
a = 8, c = 10, b = ?
The triangle is right-angled
Using pythagoras' theorem:
Hypotenuse² = opposite² + adjacent²
Hypotenuse = c, opposite = b, adjacent = a
10² = b² + 8²
b² = 10²- 8²
b² = 100 - 64
b² = 36
squre root both sides:
b = √36
b = 6 (option D)