Hello from MrBillDoesMath!
Answer:
length BC = 9
Discussion:
The base angles of the triangle equal as indicated by the single "arcs" shown. This means the triangle is isosceles and the sides oppose the base angles are equal. That is,
8x - 15 = 3x => subtract 3x from both sides
8x - 3x -15 = 3x - 3x = 0 => as 8x - 3x = 5x
5x -15 = 0 => add 15 to both sides
5x = 15 => divide both sides by 5
x = 15/5 = +3
Length of BC =
8x -15 =
8(3) - 15 =
24 - 15 =
9
Thank you,
MrB
