NAME ______________________________________________ DATE ____________ PERIOD _____
7-3
Identify Similar Triangles Here are three ways to show that two triangles are similar.
AA Similarity Two angles of one triangle are congruent to two angles of another triangle.
SSS Similarity The measures of the corresponding sides of two triangles are proportional.
SAS SimilarityThe measures of two sides of one triangle are proportional to the measures of two corresponding sides of another triangle, and the included angles are congruent.
Determine whether thetriangles are similar.
�DAC
F� � �69� � �
23�
�BE
CF� � �1
82� � �
23�
�DAB
E� � �1105� � �
23�
�ABC � �DEF by SSS Similarity.
15
129
D E
F
10
86
A B
C
Determine whether thetriangles are similar.
�34� � �
68�, so �MQR
N� � �
NRS
P�.
m�N � m�R, so �N � �R.�NMP � �RQS by SAS Similarity.
8
4
70�
Q
R S6
370�
M
N P
Determine whether each pair of triangles is similar. Justify your answer.
1. 2.
3. 4.
5. 6. 32
20
154025
24
3926
1624
18
8
65�9
465�
36
2018
24
Example 1 Example 2
Exercises
Less
on
7-3
05-42 Geo-07-873964 4/12/06 8:44 PM Page 21
Micheal Marsh
Text Box
BM2-4
Chapter 7 22 Glencoe Geometry
Study Guide and Intervention (continued)
Similar Triangles
NAME ______________________________________________ DATE ____________ PERIOD _____
Use Similar Triangles Similar triangles can be used to find measurements.
�ABC � �DEF.Find x and y.
�DAC
F� � �BE
CF� �D
ABE� � �
BE
CF�
� �198� �1
y8� � �
198�
18x � 9(18�3�) 9y � 324x � 9�3� y � 36
18�3��x
18��3
B
CA
18 18 9y
x
E
FD
A person 6 feet tall castsa 1.5-foot-long shadow at the same timethat a flagpole casts a 7-foot-longshadow. How tall is the flagpole?
The sun’s rays form similar triangles.Using x for the height of the pole, �
6x� � �
17.5�,
so 1.5x � 42 and x � 28.The flagpole is 28 feet tall.
7 ft
6 ft?
1.5 ft
Each pair of triangles is similar. Find x and y.
1. 2.
3. 4.
5. 6.
7. The heights of two vertical posts are 2 meters and 0.45 meter. When the shorter postcasts a shadow that is 0.85 meter long, what is the length of the longer post’s shadow to the nearest hundredth?
y
x32
10
2230yx
9
8
7.2
16
yx
6038.6
23
3024
36��2yx
3636
20
13
26y
x � 235
13
10 20y
x
Example 1 Example 2
Exercises
05-42 Geo-07-873964 4/12/06 8:44 PM Page 22
Micheal Marsh
Text Box
BM2-4
Exercises
Example
Chapter 11 6 Glencoe Geometry
11-1 Study Guide and InterventionAreas of Parallelograms
NAME ______________________________________________ DATE ____________ PERIOD _____
Areas of Parallelograms A parallelogram is a quadrilateral with both pairs ofopposite sides parallel. Any side of a parallelogram can be called a base. Each base has acorresponding altitude, and the length of the altitude is the height of the parallelogram.The area of a parallelogram is the product of the base and the height.
If a parallelogram has an area of A square units, Area of a Parallelogram a base of b units, and a height of h units,
then A � bh.
The area of parallelogram
ABCD is CD � AT.
Find the area of parallelogram EFGH.A � bh Area of a parallelogram
� 30(18) b � 30, h � 18
� 540 Multiply.
The area is 540 square meters.
Find the area of each parallelogram.
1. 2. 3.
Find the area of each shaded region.
4. WXYZ and ABCD are 5. All angles are right 6. EFGH and NOPQ arerectangles. angles. rectangles; JKLM is a
square.
7. The area of a parallelogram is 3.36 square feet. The base is 2.8 feet. If the measures ofthe base and height are each doubled, find the area of the resulting parallelogram.
8. A rectangle is 4 meters longer than it is wide. The area of the rectangle is 252 squaremeters. Find the length.
