Question

let angle B ne an acute angle in a right triangle. approximate the measure ot angle B to the nearest tenth of a degree when cos B = 0.2536.

Answer 1

Given that

$\cos B=0.2536$

We can find the measurement of angle B by getting the cosine inverse/arccos of 0.2536, which is calculated as follows

$\begin{gathered} B=\cos ^{-1}(0.2536) \\ B=75 \end{gathered}$

The problem requires that our answer is in the nearest tenth, hence, rounding off 75 to the nearest tenth, we get 80 degrees. Therefore, angle B has a measurement of 80 degrees.

Additional note that when computing such a problem, the calculator must be in terms of degrees, not radians.