Answer:
[tex]\bf{50 \degree }[/tex]
Step-by-step explanation:
Given:
[tex]\begin{aligned}&\sf \triangle \ ABC \\&\sf \angle B \ \cong \angle C \end{aligned} [/tex]
Solve for x
[tex]\begin{aligned}&\sf 5x-10=4x+5 \\&\sf 5x-4x=5+10 \\&\sf x=15 \end{aligned} [/tex]
Solve for ∠B
[tex]\begin{aligned}&\sf (5x-10)\degree \\=&\sf \ (5(15)-10)\degree \\=&\sf \ (75-10)\degree \\=&\sf \ 65 \degree \end{aligned} [/tex]
Solve for m
[tex]\begin{aligned}&\sf m=180 \degree -(\angle B + \angle C) \\&\sf m=180 \degree -(65 \degree + 65 \degree ) \\&\sf m=180 \degree - 130 \degree \\&\boxed{\bf{m=50 \degree }} \end{aligned} [/tex]
