Answer:
Option (b) is correct.
The measure of angle y is 39°
Step-by-step explanation:
Given : A right angled triangle with some measurements.
We have to find the value of y.
Consider the given triangle,
Using trigonometric ratios,
We know tangent is the ratio of perpendicular to its base.
Mathematically written as
![\tan\theta=\frac{Perpendicular}{base}](https://tex.z-dn.net/?f=%5Ctan%5Ctheta%3D%5Cfrac%7BPerpendicular%7D%7Bbase%7D)
So, for given triangle, ![\theta=y](https://tex.z-dn.net/?f=%5Ctheta%3Dy)
and for y, perpendicular is 8 and base is 10
Substitue, we have,
![\tan y=\frac{8}{10}](https://tex.z-dn.net/?f=%5Ctan%20y%3D%5Cfrac%7B8%7D%7B10%7D)
Simplify, we have,
![\tan y=\frac{4}{5}](https://tex.z-dn.net/?f=%5Ctan%20y%3D%5Cfrac%7B4%7D%7B5%7D)
Taking inverse of tan both side, we have,
![\tan^{-1}(\tan y)=\tan^{-1}(\frac{4}{5})](https://tex.z-dn.net/?f=%5Ctan%5E%7B-1%7D%28%5Ctan%20y%29%3D%5Ctan%5E%7B-1%7D%28%5Cfrac%7B4%7D%7B5%7D%29)
![y=\tan^{-1}(\frac{8}{10})](https://tex.z-dn.net/?f=y%3D%5Ctan%5E%7B-1%7D%28%5Cfrac%7B8%7D%7B10%7D%29)
Simplify , we have,
![y=38.65^{\circ}](https://tex.z-dn.net/?f=y%3D38.65%5E%7B%5Ccirc%7D)
Thus, the measure of angle y is 39°