16Hit 1600
Geometry and TrigonometryVery hardSine from a tangent ratio

Geometry and Trigonometry practice question

In a right triangle, tan A = 8/15 for one of the acute angles A. What is the value of sin A? (Enter your answer as a fraction.)

Answer: 8/17

tan A = opposite/adjacent = 8/15 makes the hypotenuse √(64 + 225) = 17, so sin A = 8/17.

Common wrong answers

If you answered 15/17
15/17 is cos A; sine puts the opposite side (8) on top.
If you answered 8/15
8/15 is tan A itself; sine divides by the hypotenuse 17.
If you answered 17/8
The hypotenuse is the denominator of sine, not the numerator.

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