UNIT X UNIT 3 | 115 FORMATIVE ASSESSMENT Write: Angles Write a sentence to state what all angles have in common. Do parallel lines have angles? Explain your answer. DIFFERENTIATED INSTRUCTION Scaffold Introduce students to mnemonic devices. Explain that we can create words, expressions, and clues that help us memorize difficult to remember words. Offer examples of possible mnemonics to remember the words acute and obtuse. A small angle is cute. It is a cute angle = acute angle. A large angle is obese. An “ob-ese” angle is an “ob-tuse” angle. Amplify Play Simon Says with angles. Say: Simon says draw an obtuse angle greater than 100° … Have all the students hold up their papers; the students who did it correctly stay in, while the ones who didn’t are out. Use other angles as examples and play a few rounds. B Reinforce math vocabulary Read each question as a class. Make sure students understand what an angle and parallel lines are. Call on a volunteer to identify the places where angles are formed in the picture for the class. Then have students answer the questions with a partner. Check answers as a class. ANSWERS Sample answers: 1. I see right angles, obtuse angles, acute angles, and straight angles. 2. I see many parallel lines. They are probably roads going between the rectangles of property. C Learn content-area vocabulary Work through the first item with students. Ask: What information do we know? (There are two lines, so it is an angle.) Say: Look at the angles on page 114. What kind of angle does this look like? (acute) Ask: What makes the angle acute? (It means that the angle is less than 90°.) Have students complete Activity C in pairs. Discuss the answers as a class. ANSWERS 1. acute; 2. obtuse; 3. right; 4. obtuse; 5. straight; 6. acute D Apply new knowledge of angles Direct students to flip through the story Kiki’s Adventure again and note the angles and parallel lines that appear in each illustration. Have students identify the angles by type and explain which lines are parallel. (e.g. This is an obtuse angle because is it greater than 90°). Have students complete Activity D in groups of three. ANSWERS Sample answers: right angles—windows, posters, desks; acute angles—clock hands at 2:00, book leaning on a bookshelf, stapler; obtuse angles—open scissors, open door, open book; straight angles—line around the ceiling, pencil, clock hands at 12:30; parallel lines—tiles on the floor, top and bottom of the board Practice Book p. 62 Assessment Program p. 50 COMMUNICATE PRACTICE B Look at the picture. Answer the questions. 1. What kinds of angles do you see? 2. Do you see any parallel lines? Explain. C Is each angle acute, obtuse, right, or straight? Explain. D Making connections Find items in your classroom that have: 1. 2. 3. 4. 5. 6. • right angles • acute angles • obtuse angles • straight angles • parallel lines UNIT 3 115 UNIT 3 / CONNECT TO MATHEMATICS
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