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Preview. Warm Up. California Standards. Lesson Presentation. Warm Up Solve. 1. x + 30 = 90 2. 103 + x = 180 3. 32 + x = 180 4. 90 = 61 + x 5. x + 20 = 90. x = 60. x = 77. x = 148. x = 29. x = 70. California Standards.
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Preview Warm Up California Standards Lesson Presentation
Warm Up Solve. 1. x + 30 = 90 2. 103 + x = 180 3. 32 + x = 180 4. 90 = 61 + x 5. x + 20 = 90 x = 60 x = 77 x = 148 x = 29 x = 70
California Standards Preparation for MG3.1 Identify and construct basic elements of geometric figures (e.g., altitudes, midpoints, diagonals, angle bisectors, and perpendicular bisectors; central angles, radii, diameters, and chords of circles) by using a compass and straightedge.
Vocabulary point line plane segment ray angle right angle acute angle obtuse angle straight angle complementary angles supplementary angles
Points, lines, and planes are the building blocks of geometry. Segments, rays, and angles are defined in terms of these basic figures.
A point names a location. • A Point A
C l B line l, or BC A line is perfectly straight and extends forever in both directions.
A plane is a perfectly flat surface that extends forever in all directions. P E plane P, or plane DEF D F
GH A segment, or line segment, is the part of a line between two points. H G
A ray is a part of a line that starts at one point and extends forever in one direction. J KJ K
KL or JK Additional Example 1: Naming Lines, Planes, Segments, and Rays Use the diagram to name each figure. A. a line Possible answers: Any 2 points on a line can be used.
Plane or plane JKL Additional Example 1: Naming Lines, Planes, Segments, and Rays Use the diagram to name each figure. B. a plane Possible answers: Any 3 points in the plane that form a triangle can name a plane.
JK, KL, LM, JM KJ, KL, JK, LK Additional Example 1: Naming Lines, Planes, Segments, and Rays Use the diagram to name each figure. C. four segments Possible answers: Write the two points in any order. D. four rays Possible answers: Write the endpoint first.
Caution! When naming a ray always write the endpoint first.
AB, BC, CD, AD B A C D CB, CD, DA, DC Check It Out! Example 1 Use the diagram to name each figure. A. four segments Possible answers: Write the two points in any order. B. four rays Possible answers: Write the endpoint first.
B A AB or DC C D Check It Out! Example 1 Use the diagram to name each figure. C. a line Possible answers: Any 2 points on a line can be used.
B A C D Check It Out! Example 1 Use the diagram to name each figure. D. a plane Possible answers: Any 3 points in the plane that form a triangle can name a plane. Plane R or plane ABC
1 360 An angle () is formed by two rays, or sides, with a common endpoint called the vertex. You can name an angle several ways: by its vertex, by its vertex and a point on each ray, or by a number. When three points are used, the middle point must be the vertex. Angles are usually measured in degrees ((°). Since there are 360° in a circle, one degree is of a circle.
Additional Example 2: Classifying Angles Use the diagram to name each figure. A. a right angle TQS B. two acute angles TQP, RQS
Reading Math mTQS is read as “the measure of angle TQS.”
Additional Example 2: Classifying Angles Use the diagram to name each figure. C. two obtuse angles SQP, RQT
Additional Example 2: Classifying Angles Use the diagram to name each figure. D. a pair of complementary angles TQP, RQS mTQP + mRQS = 47° + 43° = 90°
Additional Example 2: Classifying Angles Use the diagram to name each figure. E. two pairs of supplementary angles TQP, RQT mTQP + mRQT = 47° + 133° = 180° mSQP + mSQR = 137° + 43° = 180° SQP, SQR
C B 90° A D 75° 15° E Check It Out! Example 2 Use the diagram to name each figure. A. a right angle BEC
C B 90° A D 75° 15° E Check It Out! Example 2 Use the diagram to name each figure. B. two acute angles AEB, CED C. two obtuse angles BED, AEC
C B 90° A D 75° 15° E Check It Out! Example 2 Use the diagram to name each figure. D. a pair of complementary angles mAEB + mCED = 15° + 75° = 90° AEB, CED
C B 90° A D 75° 15° E Check It Out! Example 2 Use the diagram to name each figure. E. two pairs of supplementary angles mAEB + mBED = 15° + 165° = 180° AEB, BED mCED + mAEC = 75° + 105° = 180° CED, AEC
Possible answer: AD and BE Lesson Quiz 1. Name two lines in the figure. 2. Name a right angle in the figure. Possible answer: AGF 3. Name a pair of complementary angles. Possible answer: 1 and 2