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1.4 –Measure and Classify Angles & Angle Constructions. B. 1. A. C. Two different rays with the same initial point. Measured in degrees. Angle:. A ,. BAC ,. CAB,. 1. Common initial point, where rays meet. pt. A. vertex. side. The rays of the angle. side.
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1.4 –Measure and Classify Angles & Angle Constructions
B 1 A C Two different rays with the same initial point. Measured in degrees. Angle: A, BAC, CAB, 1
Common initial point, where rays meet pt. A vertex side The rays of the angle side
Point inside an angle Pt. D is in the interior of BAC D Point outside an angle Pt. E is in the exterior of BAC E
A Angle more than 0°, but less than 90° mA = 50° Angle that measures 90° mR = 90° R Angle more than 90°, but less than 180° mO = 110° O Angle that measures 180° mS = 180° S
Angle Bisector: Ray that cuts an angle in half to make 2 congruent angles QS bisects PQR P S PQS SQR mPQS = mSQR Q R Note: To name an angle use “ ”, but when stating its measure use “_______”. m
Adjacent angles: Two angles that share a common side and vertex 2 1 1 is adjacent to 2
Angle Addition Postulate: If you add two adjacent angles, it totals to get their sum. C A B D mABC + mCBD = mABD
1. Give three names for the angle shown, then name the vertex and sides. DEF FED E Vertex Sides Pt. E
1. Give three names for the angle shown, then name the vertex and sides. QVS SVQ V Vertex Sides Pt. V
2. Classify the angle as acute, right, obtuse or straight. mA = 115° obtuse
2. Classify the angle as acute, right, obtuse or straight. mA = 90° right
2. Classify the angle as acute, right, obtuse or straight. mA = 85° acute
2. Classify the angle as acute, right, obtuse or straight. mA = 180° straight
3. Use a protractor to find the measure of the angle to the nearest degree. Then classify the angle as acute, obtuse, straight, or right. obtuse 91°
3. Use a protractor to find the measure of the angle to the nearest degree. Then classify the angle as acute, obtuse, straight, or right. acute 32°
3. Use a protractor to find the measure of the angle to the nearest degree. Then classify the angle as acute, obtuse, straight, or right. straight 180°
4. Find the indicated measure. mPRS = 81+42 mPRS = 123°
4. Find the indicated measure. mWXZ = 90 – 26 = mWXZ = 64°
mNRP + mPRQ = mNRQ 8x + 7 + 4x – 1 = 78 12x + 6 = 78 12x = 72 x = 6 mPRQ = 4(6) – 1 mPRQ = 24 – 1 mPRQ = 23°
mADB + mBDC = mADC 11x – 7 + 5x – 3 = 118 16x – 10 = 118 16x = 128 x = 8 mADB = 11(8) – 7 mADB = 88 – 7 mADB = 81°
Find each indicated angle. 160° 20° 15° c = 180-90-75 = 15° a = 180-160 = 20° d = 180-90-15 = 75° b = 180-20 = 160°
Find each indicated angle. 67° 106° 74° 157° c = 180-90-23 = 67° a = 180-74 = 106° d = 180-23 = 157° b = 180-106 = 74°
mJKM = 51° mJKL = 102° 51°
mJKM = 39.5° mJKL = 79° 39.5°
5x + 2 = 7x – 6 2 = 2x – 6 8 = 2x 4 = x mABC = 20+2 +28-6 = 44° 5(4)+2 + 7(4)-6 =
5x + 13 = 9x – 23 13 = 4x – 23 36 = 4x 9 = x mABC = 45+13+81-23 = 116° 5(9)+13 + 9(9)-23 =