A look at "side-splitter

1. 7.5: Proportions in
Triangles
Objective: Use the "side-splitter"
theorem and triangle angle bisector
theorem to find missing parts of
triangles.
Standard: Geometry 4.0 (similarity) and
Geometry 7.0 (parallel lines)

2. Ex. 1) Find the value of x.
7
5 x
12

3. The Side-Splitter Theorem:
If a line is __________ to one side of a
triangle and intersects the two other
sides, then it divides those sides
_____________
=
c
a
d
b

4. Ex. 2) Find the value of x.
a) x b)
6
9
x+4
12 10 12
2x

5. Bonus Parallel Line Theorem
If three parallel lines intersect two
transversals, then the segments intercepted
on the transversals are _____________
a c
=
b d

6. Ex. 3) Solve for x and y.
6 5
x 12.5
9 y

7. Triangle-Angle-Bisector Theorem
If a ray _______ an angle of a triangle,
then it divides the _________ side into
two segments __________ to the other
two sides.
a b =
c d

8. Ex. 4) Find the value of x.
5
6 8
x

9. Assignments:
#4 7.5 Worksheet
(workbook p. 387)
#5 Textbook p. 390
#1-24 (all)
[Read examples on the
page first!]