Just multiply them together
5/7 * 7/10 = 35/70 = 1/2
7,500 x 2 = 15,000
you know you can just use a calculator...
Answer: 
Step-by-step explanation:
Given
The tower is at a height of 
the angle of depression is 
Suppose the surfer is x ft away from the base of the tower

Therefore, the surfer is at a distance of 19.31 ft from the base of the tower.
If you divide 90 to 18, you would get 5. therefore, 5cm is the answer.
Question 11 is C and also question 2 is A