The Solution:
The correct answer is 67 degrees.
Given the rhombus below:
We are required to find the measure of angle PRZ.
Considering trianglePRZ, we can apply the law of cosine to the angle of interest, which is, angle PRZ.
[tex]R=\cos ^{-1}(\frac{p^2+z^2-r^2}{2pz})[/tex]
In this case,
[tex]\begin{gathered} p=(5+5)=10 \\ z=13 \\ r=13 \\ R=\text{?} \end{gathered}[/tex]
Substituting these values in the formula, we get
[tex]R=\cos ^{-1}(\frac{10^2+13^2-13^2}{2(10)(13)})[/tex][tex]R=\cos ^{-1}(\frac{100^{}+169^{}-169^{}}{2(10)(13)})=\cos ^{-1}(\frac{100^{}}{260})=67.380\approx67^o[/tex][tex]m\angle\text{PRZ}\approx67^o[/tex]
Therefore, the correct answer is 67 degrees.
