SOLUTION: Hi, I'm having a difficult time solving the following problem: Point P lies on the perpendicular bisector of segment ST. If S has coordinates (5,14), T has coordinates (-3

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: Hi, I'm having a difficult time solving the following problem: Point P lies on the perpendicular bisector of segment ST. If S has coordinates (5,14), T has coordinates (-3      Log On


   



Question 661700: Hi,
I'm having a difficult time solving the following problem:
Point P lies on the perpendicular bisector of segment ST. If S has coordinates (5,14), T has coordinates (-3,2), and P has coordinates (-a/2,a), what is the value of a?
Any assistance would be greatly appreciated.
Thank you!

Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
 
Hi,
Point P lies on the perpendicular bisector of segment ST.
If S has coordinates (5,14), T has coordinates (-3,2)
Midpoint segment ST
(5,14),
(-3,2) Midpoint = (1,8) and slope m = (14-2)/(5-(-3)) = 12/8 = 3/2
Point P(-a/2,a) lies on the perpendicular bisector: slope -2/3
(-a/2,a)
(1, 8) slope m = %28a-8%29%2F%28%28-a%2F2%29-1%29+=+-2%28a-8%29%2F%28a%2B2%29+=+-2%2F3
| Cross Multiplying to solve
-6(a-8) = -2(a+2)
-6a + 48 = -2a - 4
52 = 4a
13 = a
and...
(-13/2,13)
( 1 , 8) +m+=+5%2F%28-15%2F2%29+=++-+10%2F15+=+-2%2F3