Answer:
78
Explanation:
Since the base angles are congruent, then the triangle is isosceles and
AB = BC , that is
5x - 19 = 2x + 11 ( subtract 2x from both sides )
3x - 19 = 11 ( add 19 to both sides )
3x = 30 ( divide both sides by 3 )
x = 10
Then
AB = BC = 2x + 11 = 2(10) + 11 = 20 + 11 = 31
Thus
perimeter = 31 + 31 + 16 = 78