FREE BRAIN LIST NEED HELP ASAP

Answer:
i am not to sure but i thinks it D and can you help me with mine i really need help i will give brainlest too
Step-by-step explanation:
Answer:
D) 9.8
Step-by-step explanation:
Because you use h^2 = a^2 + b^2
and yiu rearranged the equation for one of the sides to get x = square root of h^2 and b^2 and get 9.79... which rounds to 9.8