For an angle with measure α in a right triangle, sin α = 40/41

For an angle with measure α in a right triangle, sin α = 40/41 and tan α = 40/9. What is the value of cos α ?

1. 9/41
2. 41/9
3. 9/40
4. 9/√1,519
5. 9/√3,281

Answer

The correct answer is A.

Use the identity tan α = sins α / cos α

cos α = sin α / tan α

cos α = 9/41