How do you find the angles of a right triangle given the sides?

Guest Feb 21, 2017

1+0 Answers


sin A = a/c

cos A = b/c

tan A = a/b



sin B = b/c

cos B = a/c

tan B = b/a


You can remember this with " SOH CAH TOA. "

Sine of an angle = length of leg Opposite that angle divided by the length of the Hypotenuse

Sin = Opposite / Hypotenuse

Cosine of an angle = length of leg Adjacent that angle divided by the length of the Hypotenuse

Cosine = Adjacent / Hypotenuse

Tangent of an angle = length of led Opposite that angle / length of leg Adjacent that angle

Tangent = Opposite / Adjacent


Remember this only works on right triangles! And the "adjacent" leg cannot be the hypotenuse.

hectictar  Feb 22, 2017

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