Flashcards Pick a partner Get a set of flashcards Work on identifying angles You will have 10 minutes Go
Vocabulary Postulate – a notion that makes so much sense we don’t even have to prove it. ♥ a circle has 360° ♥ a line segment only has one midpoint ♥through any two points, there is exactly one line Theorem – a rule. It used to be an idea but it was PROVEN to be true. ♥Pythagorean Theorem: a 2 + b 2 = c 2, if c is the hypotenuse ♥Right Angle Congruence Theorem: All right angles are congruent. See proof.proof
Triangle Sum Theorem & Exterior Angle Theorem
Triangle Sum Theorem The sum of the angle measures in a triangle equal 180° m<1 + m<2 + m<3 = 180°
Exterior Angle Theorem (your new best friend) The measure of an exterior angle in a triangle is the sum of the measures of the 2 remote interior angles exterior angle remote interior angles m<4 = m<1 + m<2
an example with numbers x 82° 30°y find x & y x = 68° y = 112° 40x10x 30xfind all the angle measures y
White boards Please get: whiteboard marker eraser
3x x Find x Find the measure of each angle 3x x = 180 8x = 160 X = ° and 80° X - 1 2X - 3 X 2X Perimeter = 76 Find x and the length of each side 8x – 4 = 76 8x = 80 X = Check your work: does Equal 76?
3x - 2 Find x and then find the measure of each angle 5x - 14 Find x and then find the length of each side. 3x – 2 = 5x – = 2x 6 = x 16 units 3x x 3x + 20 = 5x 20 = 2x X = 10 50° 80°
Find all the missing angles 75° 85° 75° 95° 105° 85° 75° 105° 85° 95° 85°
Find all the missing angles 30° 110° 70° 80° 110° 70° 110° 80° 30° 80° 100°
Find the measure of angle x x 80° 40° x = x = 180 X = 60° Check your work. Does equal 180? 96° X + 12° 2X° Find the measure of each angle 2x + x = 180 3x = 180 3x = 72 X = 24 48°, 36° and 96° Do they equal 180°?
Your assignment Pg 92 – 97; , 51, 55