Respuesta :

Hello from MrBillDoesMath!

Answer:

23

Discussion:

In ΔABC side AC is 11, but as the triangle is isosceles the other leg also has length 11. Let the third, unknown side, be called x. Then

11 + 11 + x = Perimeter = 45.

11 + 11 + x = 45                 => as 11 + 11 = 22

22 + x = 45                      => subtract 22 from both sides

x = 45 -22 =  23

Thank you,

MrB