Question

How do you calculate `cos A= 0.81`?

Answer 1

See explanation.

Explanation:

`cos A = 0.81`

In this problem, we are asked to find the value of `A`, so that `cos A` is equal to `0.81`.

All you need to do is take the inverse of `cos` and set it equal to `0.81`.
So:

`cos^-1 = 0.81`
`cos^-1 ~~ 0.63` (Radians), `35.9` (Degrees)

So, `A` can be `0.63 or 35.9`, depending on which mode you are asked to use.