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Measuring Segments and Angles, Lesson 2 of 2. During today’s lesson, you will find the measures of angles. ANGLE VOCABULARY. T. 1. B. Q. TBQ has sides BT and BQ and vertex B. An angle ( ) is formed by two rays with the same endpoint. The rays are the sides of the angles
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Measuring Segments and Angles, Lesson 2 of 2 During today’s lesson, you will find the measures of angles. .
ANGLE VOCABULARY T 1 B Q TBQ has sides BT and BQ and vertex B An angle () is formed by two rays with the same endpoint. The rays are the sides of the angles and the endpoint is the vertex.
T 1 B Q Angles can be named in 3 different ways: 1. Using 3 points: TBQ or QBT 2. Using the vertex: B 3. Using a number inside the angle: 1 ALERT! When the vertex is shared, you cannot use it to name an angle.
An acute angle has a measure between 0° and 90°. A right angle has a measure a measure of exactly 90°. An obtuse angle has a measure a measure between 90° and 180°.
A straight angle has a measure of exactly 180°. Congruent angles are two angles with the same measure.
Notation for congruent angles: Use ABC DEF when referring to the actual angles. Use mABC = mDEF when referring to the measure of the angles.
A D 30° 30° A D B E C F E B F C Actual angles Use ABC DEF Measures (degrees) Use mABC = mDEF
B A O C B A O C Angle Addition Postulate If point B is in the interior of AOC, then mAOB + mBOC = mAOC Also, if AOC is a straight angle, then mAOB + mBOC =180°
T W R S EX. #2 What is mTSW if the mRST = 50 and mRSW = 125? Angle Addition Postulate mRST + mTSW = m RSW Substitute: 50 + mTSW = 125 Solve: mTSW = 75
Final Checks for Understanding • Name four ways by which we classify angles based upon their degree measure. • Use the diagram below to answer the following questions: a. Is DEF FEG? b. Is Is DEF FEG? c. Are DEF and FEH adjacent? F G 45 45 D E H
HOMEWORK ASSIGNMENT PAGES 30-32: 16-28, 47-48, 59-61,65-66,75-76 Show work when necessary!