Name: ___________________

Date:___________________
kwizNET Subscribers, please login to turn off the Ads!
Email us to get an instant 20% discount on highly effective K-12 Math & English kwizNET Programs!

Geometry
2.23 Properties of Similar Triangles

Congruency and Similarity: Figures that have same shape and size are said to be congruent, whereas figures need to be of the same shape but not necessarily of the same size for them to be similar.

Properties of similar triangles
Property 1: If in two triangles, angles are equal, then their corresponding sides are proportional and hence the triangles are similar. This property is called AAA postulate.
Property 2: If one angle of two triangle is equal to the other and their sides are proportional, then the triangles are similar by SAS postulate.
Property 3: If two angles and one side of two triangles are equal, then they are similar by ASA postulate.

Example: In triangle ABC, prove that ABC and DEF are similar.

Solution:: In triangles ABC and ADE, we have
angle A = angle A (common angle)
angle B = angle E (90o)
Hence triangles ABC and ADE are similar.

Directions: Solve the following problems. Also write at least 5 examples of your own.
Q 1: A vertical stick 12 cm longs casts a shadow 8 m long on the ground. At the same time a tower casts a shadow 40 m on the ground. Find the height of the tower.
60 m
45 m
35 m

 Q 2: Find angle EAB

45o
75o
60o

Q 3: Find angle DCE

30o
45o
80o

 Q 4: The perimeters of two similar triangles are 30 and 20 respectively. If one side of the first triangle is 12, determine the corresponding side of the other triangle.
15 cm
8 cm
12 cm

Question 5: This question is available to subscribers only!

 Question 6: This question is available to subscribers only!


Subscription to kwizNET Learning System costs less than $1 per month & offers the following benefits:

  • Unrestricted access to grade appropriate lessons, quizzes, & printable worksheets
  • Instant scoring of online quizzes
  • Progress tracking and award certificates to keep your student motivated
  • Unlimited practice with auto-generated 'WIZ MATH' quizzes
  • Child-friendly website with no advertisements

© 2003-2007 kwizNET Learning System LLC. All rights reserved. This material may not be reproduced, displayed, modified or distributed without the express prior written permission of the copyright holder. For permission, contact info@kwizNET.com
For unlimited printable worksheets & more, go to http://www.kwizNET.com.