
Sarah K. answered 03/29/19
Tutor for the SAT for over 10 years
When a line is bisected, that means that both sides are equal. Ex. If a line of length 10 is bisected, then each segment is 5.
8x+12 6x+18
•---------------|--------------•
A B C
By definition the length of AB = the length of BC therefore
AB = BC
8x+12 = 6x+18
a) What is the value of x?
8x+12 = 6x+18 Solve for x, put like-variables on the same side
8x-6x = 18-12 Simplify
2x = 6 Divide both sides by 2
x = 3
b) What is the length of AB?
We found that x = 3 and given that AB = 8x+12, we plug x into that equation.
AB = 8x + 12
AB = 8(3) + 12
AB = 24 + 12
AB = 36
c) What is the length of AC?
Since the line is bisected, AB = BC, so you can double AB to get the answer 2(AB) = 2(36) = 72
Or you can solve for BC using x and add the two together to make sure your equations are correct.
BC = 6x+18
BC = 6(3) + 18
BC = 18 + 18
BC = 36
AC = AB + BC
AC = 36 + 36
AC = 72