Given:
In triangle UVW, X is the midpoint of UV and Y is the midpoint of VW.
![m\angle XYV=7x+21](https://img.qammunity.org/2022/formulas/mathematics/high-school/dzmi3qtazc7eujjr8gqt6cs6ylms3bstlg.png)
![m\angle UWY=91-7x](https://img.qammunity.org/2022/formulas/mathematics/high-school/4aho51fc99gpbt05ovz7hhx2rgf55y20d0.png)
To find:
The measure of angle XYV.
Solution:
Since X is the midpoint of UV and Y is the midpoint of VW, therefore XY is the mid-segment of the triangle UVW and parallel to the base of the triangle, i.e., UW.
If a transversal line intersect two parallel lines, then the corresponding angles are congruent and their measures are equal.
[Corresponding angle]
![m\angle XYV=m\angle UWY](https://img.qammunity.org/2022/formulas/mathematics/high-school/8a8alrnm3lbw1n4n9yntga4m6jiyy2evtj.png)
![7x+21=91-7x](https://img.qammunity.org/2022/formulas/mathematics/high-school/q4wb128x4qnil6kdihalt81pqhcssqzgim.png)
We need to solve this equation for x.
![7x+7x=91-21](https://img.qammunity.org/2022/formulas/mathematics/high-school/klm2twdew0ygg85r9an458jpkkgv644p3n.png)
![14x=70](https://img.qammunity.org/2022/formulas/mathematics/high-school/pssrtw3aei3by8cioiut01co73sjh2j8q1.png)
![x=(70)/(14)](https://img.qammunity.org/2022/formulas/mathematics/high-school/hcvopbsimk1af94d3w3dlrdcc12exy70v4.png)
![x=5](https://img.qammunity.org/2022/formulas/mathematics/high-school/vndazmbyqu3wu39zuuyki1lbj4enalp9m1.png)
Now,
![m\angle XYV=7x+21](https://img.qammunity.org/2022/formulas/mathematics/high-school/dzmi3qtazc7eujjr8gqt6cs6ylms3bstlg.png)
![m\angle XYV=7(5)+21](https://img.qammunity.org/2022/formulas/mathematics/high-school/os8mao0hu2ifolnopzgq8yovdqot44jj89.png)
![m\angle XYV=35+21](https://img.qammunity.org/2022/formulas/mathematics/high-school/v84csfoo3oual8wvnvwkm6k71panbdjhso.png)
![m\angle XYV=56](https://img.qammunity.org/2022/formulas/mathematics/high-school/keu53tdxjernczc7h2p7wpafwmi0fw8ey3.png)
Therefore, the measure of angle XYV is 56 degrees.