UNIT X 114 | UNIT 3 Instructional Routine: Mathematics p. Txxxii Angles A • Use graphics to learn new concepts Tell students to read the informational text. Point out angles on the page with your finger. Say: An angle occurs when two lines meet. It is measured in degrees. Point at the lines that meet and then the degree symbol as you speak. As you point to each angle on the page, say: This is an angle. Write the boldfaced words on the board and ask the meaning of each: right angle, obtuse angle, acute angle, straight angle. Work as a class to define each word on the board. (A right angle measures 90°. It makes a square corner. An obtuse angle measures more than 90°. An acute angle measures less than 90°. A straight angle measures 180°. It makes a line.) • Listen actively to build academic vocabulary Use the vocabulary routine for parallel lines and protractor. Play the audio and direct students to listen closely for the new words as they follow along. Then replay the audio to build comprehension of the content. • Learn content area vocabulary Point out the word vertex in the last paragraph and the context around it. Ask: How can we figure out the meaning of vertex? (It is defined in the paragraph.) What is that definition? (“the corner of the angle”) What does that mean? (the place where the two lines meet to form an angle) Direct students to identify the vertices (plural of vertex) on the page by their letters assigned to the points on the lines in each graphic. (T, F, K, H). Essential Question: What are the properties of angles? Use academic language Read the Essential Question aloud and elicit answers. Direct students to use pictures and numbers to illustrate what the properties of angles are. ANSWERS Angles occur when two lines meet; they are measured in degrees between 0 and 180. EXPLORE AND LEARN DIFFERENTIATED INSTRUCTION Scaffold Draw several straight lines on the board. Some of the lines should meet. Review the idea that angles occur only when lines meet. Direct students to circle the places where two lines meet to indicate the angles. Correct their answers. Amplify Give students protractors and ask them to go around the room and find three angles: one acute angle, one obtuse angle, and one right angle. Then have them share the angles they find with a partner. Angles A Read the informational text. Working with Angles Angles are measured in degrees. We name angles by their measures. Look at these angles. A right angle measures 90°. It makes a square corner. An acute angle measures less than 90°. An obtuse angle measures more than 90°. A straight angle measures 180°. It makes a line. Two lines that do not meet are parallel lines. When lines meet, they make angles. You use a protractor to measure angles. Use the vertex, the corner of the angle, as your guide when measuring angles. What are the properties of angles? ? ESSENTIAL QUESTION This angle measures 55°. It is an acute angle. S T U G H I This angle measures 130°. It is an obtuse angle. J K L E F G UNIT 3 114 CONNECT TO Mathematics UNIT 3 / CONNECT TO MATHEMATICS
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