The answer is 6.
Division is the opposite of multiplication and 3x6 is 18
Answer:
Part 1) 
Part 2) 
Part 3) 
Step-by-step explanation:
Part 1) Find AC
we know that
In the right triangle ABC of the figure
Applying the Pythagorean Theorem

substitute the given values


Part 2) Find the measure of angle A
we know that
In the right triangle ABC
----> by TOA (opposite side divided by the adjacent side)
substitute the values

using a calculator

Part 3) Find the measure of angle C
we know that
In the right triangle ABC
----> by complementary angles
substitute the given value


Check the picture below.
make sure your calculator is in Degree mode.
The answer is D! if you sub them in :)