LESSON 1–4 Angle Measure
ray degree right angle acute angle opposite rays angle obtuse angle angle bisector opposite rays angle side vertex interior exterior Vocabulary
A. Name all angles that have B as a vertex. Angles and Their Parts A. Name all angles that have B as a vertex. Answer: Example 1
Angles and Their Parts B. Name the sides of 5. Answer: Example 1
Angles and Their Parts C. Example 1
A. A. B. C. D. Example 1a
B. A. B. C. D. none of these Example 1b
Which of the following is another name for 3? B. C. D. Example 1c
Concept
A. Measure TYV and classify it as right, acute, or obtuse. Measure and Classify Angles A. Measure TYV and classify it as right, acute, or obtuse. Answer: mTYV = 90, so TYV is a right angle. Example 2
Answer: 180 > mWYT > 90, so WYT is an obtuse angle. Measure and Classify Angles Answer: 180 > mWYT > 90, so WYT is an obtuse angle. Example 2
Measure and Classify Angles Example 2
A. Measure CZD and classify it as right, acute, or obtuse. A. 30°, acute B. 30°, obtuse C. 150°, acute D. 150°, obtuse Example 2a
B. Measure CZE and classify it as right, acute, or obtuse. A. 60°, acute B. 90°, acute C. 90°, right D. 90°, obtuse Example 2b
C. Measure DZX and classify it as right, acute, or obtuse. A. 30°, acute B. 30°, obtuse C. 150°, acute D. 150°, obtuse Example 2c
Measure and Classify Angles INTERIOR DESIGN Wall stickers of standard shapes are often used to provide a stimulating environment for a young child’s room. A five-pointed star sticker is shown with vertices labeled. Find mGBH and mHCI if GBH HCI, mGBH = 2x + 5, and mHCI = 3x – 10. Example 3
mGBH = mHCI Definition of congruent angles Measure and Classify Angles Step 1 Solve for x. GBH HCI Given mGBH = mHCI Definition of congruent angles 2x + 5 = 3x – 10 Substitution 2x + 15 = 3x Add 10 to each side. 15 = x Subtract 2x from each side. Example 3
Step 2 Use the value of x to find the measure of either angle. Measure and Classify Angles Step 2 Use the value of x to find the measure of either angle. . Answer: mGBH = 35, mHCI = 35 Example 3
Find mBHC and mDJE if BHC DJE, mBHC = 4x + 5, and mDJE = 3x + 30. A. mBHC = 105, mDJE = 105 B. mBHC = 35, mDJE = 35 C. mBHC = 35, mDJE = 105 D. mBHC = 105, mDJE = 35 Example 3
LESSON 1–4 Angle Measure