Download Name: TP: ____ CRS Geometry Content Objective 6.4 Identify and

CW#48: Classify Triangles /
Find Missing Sides & Angles
Geometry
Name: ____________________________ TP: ____
CRS
Objective
Geometry Content
6.4 Identify and explain characteristics of different types of triangles
6.5 Use exterior angle theorem to find a missing angle
**CHECK FOR UNDERSTANDING WHITEBOARD ACTIVITY!!**
1) Classify the triangle by its sides.
2) Classify the triangle by its angles.
STAY READY.
Example 1: Classify RST by its sides. Then
determine if it is a right triangle.
3) Graph the given triangle and classify it by its
sides. Then determine if it is a right triangle.
a) A(3, l), B(3,4), C(7, 1)
Step 1: Use the _______________________________ to
determine the side lengths.
RS =
ST =
TR =
Step 2: Use the _______________________________ to check
for right angles.
Step 2: Use the _______________________________ to check
for right angles.
RS =
ST =
TR =
4) Graph the given triangle and classify it by its sides. Then determine if it is a right triangle.
A(2, 2), B(6, 2), C(4, 8)
STAY READY.
Discovering Exterior Angle Theorem…
5) Find the value of y.
6) Find the value of x.
Step 1: Add the interior angles:
Step 2: Subtract the interior angles from 180
degrees to find the third angle of the triangle
(triangle sum theorem). Label the angle in the
triangle:
Step 3: Subtract Step 2 from 180 degrees to find y
(supplementary angles). Label the angle in the
triangle:
Step 1: Add the interior angles:
Step 2: Subtract the interior angles from 180
degrees to find the third angle of the triangle
(triangle sum theorem). Label the angle above.
Step 3: Subtract Step 2 from 180 degrees to find y
(supplementary angles). Label the angle above.
7) What observations can you make about Step 1 and Step 3? Explain what the exterior angle theorem is
in your own words.
The ______________________________________________ theorem states that the measure of an exterior angle of a
triangle is equal to the sum of the measures of the two nonadjacent angles.
STAY READY.
Directions: For the problems that follow, a) Create a bulleted list of the angle
properties/theorems/postulates you used to determine the missing angles, and b) Find the missing angle.
8)
9)
Example 3: Find the measure of the exterior angle
shown.
10) Find the measure of the exterior angle shown.
Independent Practice

Complete in your notebooks: Pages 211 – 212; #1 – 6, 11 – 13, 17 – 19, 32 – 37
STAY READY.