Answer:
Step-by-step explanation:
we know A + B + C = 180 for a triangle
isosceles have the same angles on the base sides
so our equation can be rewritten with that
A + A + C = 180
2A+C=180
so we are also told that A is 9 less than 4 times the vertex .. vertex is the point or top... in this case.. or C
A= 4C-9
now plug it in
2(4*C-9) + C =180
8C-18+C=180
9C-18=180
9C=198
C = 22
