Question

A right triangle has side lengths 8, 15, and 17 as shown below.
Use these lengths to find cos A, tan A, and sin A.
Cos A = ľ
tan A =
sin A =

Answer 1

Without the figure we can't tell which angle A is.  We'll write it both ways; you'll have to match the appropriate one to your problem.

If A is the angle opposite 17 then its the right angle.  They're probably not giving us that problem.

If A is the angle opposite 15 then

$\cos A = \dfrac{8}{17}$

$\sin A = \dfrac{15}{17}$

$\tan A = \dfrac{15}{8}$

If A's the one opposite 7 then cosine and sine swap and tangent gets flipped:

$\cos A = \dfrac{15}{17}$

$\sin A = \dfrac{8}{17}$

$\tan A = \dfrac{8}{15}$