What is the answer to this question? I need help.

i did it myself and i got 4.2 (b) hope its right

step-by-step explanation:

this is answer of 144 cubic meters

the answer is 99.

first, you divide the triangle in two, tô form a retangle triangle. after, using pythagoream theorem:

18^2 = 14^2 + (x/2)^2

(x^2/4) + 196 = 324

x^2/4 = 324 - 196

x^2/4 = 128

x^2 = 512

x = √512

x = √2^9

x = 16√2 cm

i hope i you.