中等MATH-TRIG-001
In a right-angled triangle, the side opposite θ is 5 and the hypotenuse is 13. What is sin θ?
A. 5/13✓ 答案
B. 12/13
C. 5/12
D. 13/5
解說
sin θ = opposite / hypotenuse = 5/13. The third side of the 5-12-13 triangle is 12, so 12/13 is cos θ and 5/12 is tan θ. 13/5 is the reciprocal of sine.