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Discover that Vertical <s are ____. GET OUT A SHEET OF PAPER and pencil. I’ll bring you a Protractor. Draw two intersecting lines Name the 4 angles created by the lines Measure all of the angles. On your sheet of paper answer the question: What do you notice about the vertical angles. 1.
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Discover that Vertical <s are ____ GET OUT A SHEET OF PAPER and pencil. I’ll bring you a Protractor. • Draw two intersecting lines • Name the 4 angles created by the lines • Measure all of the angles. • On your sheet of paper answer the question: What do you notice about the vertical angles. 1 2 4 3 <2&4 are vertical <1&<3 are vertical
Length on a Coordinate Plane: Must use the Distance Formula. given 2 points: Example: Find CD if C(-2,8) and D(4,0) • Substitute the x and y coordinates in the problem into the distance formula • Solve for the distance C D
Midpoint Formula In a Coordinate Plane: where the endpoints are (x1,y1) and (x2,y2) Example: Find CD if C(-2,8) and D(4,0) C Midpoint D
Section 1.7 – Special Angle Pairs Sept. _____, 2009
Adjacent Angles Two angles with a common vertex and a common side, but no common interior points. A A Ex. 2 Ex. 1 B C C B D D <ABC and <CBD are adjacent Pt. B is the common vertex and BC is the common side <ABC and <ABD are non-adjacent Pt. B is the common vertex and BA is the common side BUT They have common Interior points!
Vertical Angles Two non-adjacent angles formed by intersecting lines <1 and <3 are vertical 2 1 3 <2 and <4 are vertical 4 Vertical angles are congruent If m<1 = 50 what is the m<3? _______
Linear Pair Two adjacent angles whose noncommon sides form opposite rays. C 2 1 A B D <1 and <2 form a linear pair. Linear pairs always equal 180º.
Very useful!! Notice the relationship between Linear Pairs and Vertical Angles Line AB has 2 pairs of adjacent angles that are also linear pairs: <1&<2 , <3&<4 C B 2 1 3 4 A D ** REMEMBER THIS WHEN WE GET TO SUPPLEMENTARY ANGLES**
Complementary Angles Two angles that have a sum of 90º 60º 30º A 1 2 B <1 and <2 are Complementary <A and <B are Complementary
Supplementary Angles Two angles that have a sum of 180º <1 and <2 are Supplementary 2 1 *****LINEAR PAIRS ARE ALWAYS SUPPLEMENTARY***** <A and <B are also Supplementary 80º B A 100º
Perpendicular lines Two lines that intersect to form a right angle. Show as: B A C 1 2 3 4 D
There are a lot of ways we can use these definitions to find Angle Measures. We’ll do this tomorrow.Your homework is PW 1.7 #1-6