The other person is literally wrong. The answer is D. Supplementary because two angles that add up to 180 are supplementary angles.
The answer to the question is C.
To find the third side of a triangle (there are two answers you could get), you need to use the Pythagorean formula: a^2+b^2=c^2. First answer, 20^2+30^2=c^2. Solve for c. c=36.06. The second answer, 20^2+b^2=30^2. Solve for b. b=26.36.
Answer:
Assuming "the speaker takes up 1/6 of the internal volume"
volume is 9³ in³
you want the remaining volume, which is 5/6 of the total
(5/6)9³ = 607.5 in³
double that if you want the remaining volume for BOTH speakers....
