ISBN Copyright 2015 The Continental Press, Inc.

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1 Table of COntents Introduction 3 Format of Books 4 Suggestions for Use 7 Annotated Answer Key and Extension Activities 9 Reproducible Tool Set 187 ISBN Copyright 215 The Continental Press, Inc. Excepting the designated reproducible blackline masters, no part of this publication may be reproduced in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of the publisher. All rights reserved. Printed in the United States of America.

2 37 Measuring and Drawing Angles Pages 267 and 268 Objective To use a protractor to measure and draw angles 1 Introduction Distribute protractors to individual or pairs of students; if necessary, copy the blackline master in the back of this Teacher s Edition on heavy paper and give each student one to cut out and use. Review that an angle is measured in units called degrees. Discuss the protractor and guide the students in reading the two scales. Emphasize that one ray should always be lined up with on a scale and that scale, whether the inner or outer, should be used to read the measure at the other ray. Think About It Students should determine that there are two acute angles of 45 each and one right angle of 9. Common Core State Standard Measure angles in whole-number degrees using a protractor. Sketch angles of specified measure. Vocabulary protractor: a tool used to measure the size of an angle Connections to Standards for Mathematical Practice Model with mathematics. Use appropriate tools strategically. Attend to precision. /ABC and /DEA; /BCD and /CDE E 5 UNIT 5 The Continental Press, Inc. DUPLICATING THIS MATERIAL IS ILLEGAL.

3 PAgeS 269 AND 27 /BAE 5 15, /BCD and /CDE 5 135, /ABC and /DEA 5 6 /BAE, /BCD, and /CDE /ABC and /DEA A B 1 8 B C Focused Instruction In the first activity, students measure the five angles of an irregular pentagon. They are guided in correctly aligning the protractor. They then name each angle using the three-letter convention and identify its measure in degrees. Finally, they sort the angles as obtuse or acute. Next, students draw an angle of 118 using a protractor given on the page. Questions guide them in reading the correct scale. Conclude the Focused Instruction section by having students draw or measure angles to answer two additional questions. 118 Answers will vary depending on direction the student draws his/her angle. /FGH is 3, /HGJ is 15 Extension Activity To pairs of students, distribute copies of a local city or regional map on which streets and roads are shown clearly, a protractor, and colored markers. Direct the students to study the maps and find and mark examples of right, acute, obtuse, and straight angles as formed by roads. Students should measure the angles and write the measure inside each angle. The Continental Press, Inc. DUPLICATING THIS MATERIAL IS ILLEGAL. UNIT 5 161

4 PAgeS 271 AND Guided Practice Students should complete the Guided Practice section on their own. Offer assistance as needed, pointing out the reminder and hint boxes along the right side of the page Independent Practice Answer Rationales 1 Parts A, B, C, and D To find each angle, set the center mark of the protractor on the point marked A at the center of the circle. Then align on the protractor with one ray and read the correct angle size on the scale to find the ray for the other point. Then label the points for the rays. The rays of the circle are 3 apart, so any two adjacent rays indicate a 3 angle; angle BAC is acute. Any three adjacent sections make an angle of 9 ; angle DAE is a right angle. Any five adjacent sections make an angle of 15 ; angle GAF is obtuse. Any six adjacent sections make an angle of 18 ; angle HAJ is a straight angle. acute right Any two adjacent lines, labeled B and C, are correct. Any two lines, labeled D and E, separated by 3 sections are correct. obtuse Any two lines, labeled G and F, separated by 5 sections are correct. straight Any two lines, labeled H and J, separated by 6 sections are correct. 162 UNIT 5 The Continental Press, Inc. DUPLICATING THIS MATERIAL IS ILLEGAL.

5 PAgeS 273 AND 274 Either of these quadrilaterals is correct if it has two 6 angles and two 12 angles. S U 2 Align the vertex of the angle with the center point of the protractor and one ray with. Read the measure the other ray passes through: 14. Choice D is correct. Choices A and B are the result of reading the scale from the wrong direction, and choice C is an inaccurate reading. 3 A quadrilateral is a plane figure with four sides. The student should understand how to measure and draw angles with a protractor and how to arrange the sides and angles of a quadrilateral to complete a plane figure with given measures. Either a parallelogram or a trapezoid would fit the given specifications. 4 The shared vertex of the angles is point T, so draw ray TU first. Align this ray with on the protractor and point T at the center, then mark off an angle of 55, and draw ray TS. Flip the protractor, keeping T at the center and aligning TU with at the other end. Then mark off an angle of 85 and draw ray TX. T X F X 5 Part A An obtuse angle is greater than 9 and less than 18, so the angle on the left is obtuse. In the three-letter naming convention for angles, the middle letter always names the vertex, so this point should be labeled E and points D and F may be attached to either ray. Part B An acute angle is less than 9, so the angle on the right is acute. The vertex should be labeled Y and points X and Z attached to either ray. D E Y Z Draw one ray, then use the protractor to mark off a 9 angle at one end, and then draw the second ray. Point G names the vertex in angle FGH and points F and H should be attached to either ray. By definition, an angle of 9 is a right angle. F G H right The Continental Press, Inc. DUPLICATING THIS MATERIAL IS ILLEGAL. UNIT 5 163