The height h of the equilateral triangle below is given by y= 5 cot theta where theta = 30 degrees a) 2.9 b)4.3 c)7.1 d)8.7

To solve this we can take two different approaches:

1. We can substitute theta by 30° and evaluate our expression using a calculator: 




2. We can use the unitary circle and the fact that , so we can rewrite our expression as follows:



From our unitary circle we can check that  and . 
Lets replace those values in our expression and simplify:




Either way we can conclude that the correct answer is: D)8.7