Simplify cot θ sec θ. sin θ cos θ sec θ csc θ

To simplify our expression, we are going to use tow trigonometric identities: 
1. 
2. 

Using those trig identities, we can rewrite our expression an simplify:


Finally, we can use the trig identity:  to completely simplify our expression:


We can conclude that cot θ sec θ=csc θ

The answer is: a = about 63.59ft2 for 15