Question

Please help with the problem attached.

Answer 1

Explanation:

You have to use the Law of Cosines here to find angle R. Namely,

`r^2=q^2+s^2-2qscosR`

Filling in:

`99^2=54^2+141^2-2(54)(141)cosR` and

`9801=2916+19881-15228cosR` and

`9801=22797-15228cosR` and

`-12996=-15228cosR` so

`.853427896=cosR`

Use the 2nd button and then the cos button to find the angle that has a cos of that decimal. You should get, as long as you are in degree mode, that angle R = 31.4°