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Distance & Midpoints Angle Measure. Notes 2 – Sections 1.3 & 1.4. Essential Learnings. Students will understand and be able to find distance and the midpoint of a segment. Students will be able to construct, copy and bisect segments.
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Distance & MidpointsAngle Measure Notes 2 – Sections 1.3 & 1.4
Essential Learnings • Students will understand and be able to find distance and the midpoint of a segment. • Students will be able to construct, copy and bisect segments. • Students will understand and be able to measure and classify angles. • Students will be able to identify and use congruent and special pairs of angles. • Students will be able to identify perpendicular lines.
Vocabulary • The distance between two points is the length of the segment with those points as the endpoints. • Midpoint – the point halfway between the endpoints of a segment. x1 M x2
Distance Formula • If P has the coordinates (x1,y1) and Q has coordinates (x2,y2) then:
Example 1 • Find the distance between the pair of points. M(4,0) and L(-2,-3).
Midpoint Formula • If has the endpoints P(x1,y1) and Q(x2,y2) in the coordinate plane, then the midpoint M of is:
Example 2 • Find the coordinates of the midpoint of a segment with endpoints W(12,2) and X(7,9).
Example 3 • Find the coordinates of the missing endpoint if B is the midpoint . A(1,7) and B (-3,1)
Example 4 • Suppose M is the midpoint of . Use the given information to find the missing measure or value. FM = 5x+13, MG = 5-3x, FG = ?
Constructions • Need compass! Construct segment Copy segment Bisect a segment
Vocabulary • Ray – begins at a point and extends indefinitely in one direction. • Angle – formed by two rays that have a common end point. Q P PQ
Vocabulary • Vertex – the common endpoint of an angle. • Side – one of the rays that make up an angle. • Opposite rays – rays that share a common endpoint and are collinear.
Angles • Naming angles – use three letters with the vertex as the middle letter or can name the angle using the vertex but only if there is only one angle located at that vertex. J 2 L K
Example 5 • Name all angles that have B as the vertex. E D B F A C G
Example 6 • Write another name for each angle. ∠DCB ∠BAC ∠4 D B 2 5 1 3 4 A C E
Measures of Angles • Angles are measured in degrees. Use your protractor to measure angles.
Classifying Angles Acute angle Right angle Obtuse angle m∠A< 90⁰ m∠A= 90⁰ 90⁰<m∠A <180⁰ A A A
Copying an Angle • Use your compass.
Angle Bisector • Angle bisector – a ray that divides an angle into two congruent angles. C ∠ABC ≅ ∠CBD 70⁰ 70⁰ A D B
Constructing Angle Bisector • Use your compass.
Example 7 Ray QS bisects ∠PQT. m∠PQT=60⁰ andm∠PQS=4x+14, solve for x. T S P Q R
Example 8 Ray KM bisects ∠NKL. m∠MKL=3x+13 andm∠NKM=6x-2, m∠NKL=? N M J K L
Assignment Page 32: 19-29 odd, 41-53 odd Page 41-44: 20-25, 37-41 odd, 64, 65 Signed Slip Cover Textbook