Respuesta :

BC = 48

<c and <b are congruent (as shown in picture)
AC and AB are congruent because of Base Angles Theorem

Make an equation for the two side lengths:
x + 8 = 2x - 1
x - 1 = 8
x = 9

Then you can plug in for BC
3(17) - 3 
51 - 3
48 Units