As you can see in the picture, this is 6-8-10 right triangle.
One of angles is 90° so you can find others
[tex] \tan( \alpha ) = \frac{opp}{adj} [/tex]
8/6 = 4/3
6/8= 3/4
tan-1(4/3) = 36.9 °
tan-1(3/4) = 53.1 °
tan<R= 53.1 °
Hope this helps ^-^
