Angles and Their Measures Chapter 1 Section 1.4 Angles and Their Measures
Warm-Up Write the distance formula. Find the distance between the points (-2, 5) and (0, 7).
• Angle: Composed of two rays that have the same initial point B Vertex Exterior Sides Interior BAC, CAB, or A The angle can be named 3 ways:
Name the 3 angles in the picture PQS Top angle SQR Bottom angle PQR Whole angle
Congruence Two angles are congruent if they have the same measure If ABC PQR then mABC = mPQR Two segments are congruent if they have the same measure Congruence: Having the same size and shape
Protractor Postulate A protractor is used to measure angles Angles are measured using Degrees
Angle addition postulate R • T P RST RSP PST If P is in the interior of RST then mRSP + mPST = m RST
4 angle types A A Acute Angle Right Angle 0° < mA < 90 ° • A A Straight Angle mA = 180 ° Obtuse Angle 90° < mA < 180 °
m TMF = m TMW + m WMF m TMF = 27 + 63 m TMF = 90 m XLV = m XLC + m CLV m XLV = 39 + 103 m XLV = 142