Question

∠A is an acute angle in a right triangle. Given that cosA=12/13, what is the ratio for sinA?

Answer 1

SinA=5/13
if it is a right triangle we can use the Pythagorean theorem to solve for the missing side. 13 = hypotenuse, and 12 = a leg.

`a^(2) +b^2=c^2`
Plug in values

`12^(2) +b^2=13^2`
subtract 12 squared from both sides

`b^2=13^2 -12^(2)`

`13^2 -12^(2) =25`
squared root of 25 is 5. the missing leg is 5 so sin is opp/hyp or 5/13