Geometry 1.4 SWLT Measure and Classify Angles
Classifying Angles Acute Angles: 0 < m A < 90 Right Angles m A = 90 A A
Classifying Angles (Con’t) Obtuse Angles 90 < m A < 180 Straight Angle m A = 180 A A
Angle Addition Postulate If P is in the interior of RST, then the m RST is equal to the sum of the measures of PST and RSP P S R T
Applying the Angle Addition Postulate Given: m GFJ = 155 , m GFH = (4x + 4) and m HFJ = (4x – 1) Find m GFH & m HFJ m GFJ = m GFH + m HFJ 155 = (4x + 4) + (4x – 1) 155 = 8x = 8x x = 19 m GFH = (4(19) + 4) = 80 m HFJ = (4(19) – 1) = 75 G F J H
Angle Bisectors Statement: If WY bisects ZWX, then XWY ZWY Converse: If XWY ZWY, then WY bisects ZWX X Y W Z
Using Angle Bisectors Given: KM bisects LKN and m LKM = 78° Find m LKN Solution: LKM ≅ MKN m LKN = m LKM + m MKN m LKN = 78° + 78° m LKN = 156° L M K N