Multiple choice general knowledge math & puzzles

Angle A is an acute angle and sin(A) = 11/14. What is the value of cos(A)?

  1. 3/14

  2. ?3 / 14

  3. 5?3 / 14

  4. 5/14

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

For any angle A, sin²(A) + cos²(A) = 1, so cos(A) = √(1 - sin²(A)). Given sin(A) = 11/14, we have cos(A) = √(1 - 121/196) = √(75/196) = √75/14 = 5√3/14. The cosine is positive since A is acute.