This document discusses using similar triangles to solve a problem involving missing lengths. It provides the definition of similar triangles as (1) having congruent angles and (2) having proportional corresponding sides. It then presents two triangles with labeled sides and asks to determine the length of side d using the property of similar triangles.

1. Problem Solving with Similar Triangles
but, uh ... not quite like this ...
Who needs Pythagoras' theorem

2. Mental Math
Find the missing term in each (6) Find 75% of 42 31.5
of the next 5 proportions:
61.5
(7) Find 75% of 82
9
For questions (8) and (9) consider this spreadsheet:
B C D
A
1 Name Hourly Wage Hours Earnings
2 Abbie 7 4
20
Barry 8 5
3
Cindy 9 6
4
David 10 7
5
18
(8) What formula goes in cell D2?
=B2*C2
(9) Name the cell in which
12 it makes most sense to
D6
calculate Total Earnings.
(10) What is 66 x 11? 726
1

3. Similar Triangles
(1) All angles are congruent (equal).
(2) The ratios of all corresponding sides are equal.
x= 2

4. e
bl
a
cl
y
c
re
h
at
m
D
H
∠
G
= C
(a) State the pairs of corresponding angles. B
F
∠ D and ∠H
∠ C and ∠G
∠ B and ∠ F
(b) Write the ratios of corresponding sides.
CD
BD
BC =
=
FG FH GH
GH

5. The two triangles are similar. Determine the length of side d.