Measuring With Unit Angles Literature Link: Sir Cumference and the Great Knight of Angleland by Cindy Neuschwander 5-6 pages per day Lesson 16-4 CCSS 4.MD.5; 4.MD.5.a,b; 4.G.1

MATH Essential Questions How can lines, angles, and shapes be described, analyzed, and classified? MATH Essential Questions

MATH Essential Questions How are angles measured, added, and subtracted? MATH Essential Questions

Warm Up Put these fractions into their simplest form. 6/12 3/18 10/15 4/24

Think and Write What measurement tools do you know of? Sample answers include yardstick, ruler, measuring tape, clock, scale, and measuring cup

Today’s Lesson In this lesson, you will learn how to use a tool to measure angles. Let’s look at the Envision Video for this lesson and take the quiz.

Measuring Tools Cut out the triangles. Arrange them around a center point on the Pattern Block Grid Paper. How many vertices will it take to complete 360º? Did you discover that you needed 6 triangles? Now take the 360º and divide it by 6 to get the number of degrees for each angle around the center point. You now know that you can label each triangle as 60º. Hand each student a piece of square paper (a post-it would work well). Have them fold it horizontally, then vertically. Then fold diagonally twice so that there is a total of 8 wedges. Practice using these unconventional wedge units to measure angles. I suggest doing this as a 10 minute team activity to break up the lesson and get students used to using unconventional measuring units.

Determining the Number of Degrees for the Hexagon Draw a straight line on the Pattern Block Grid Paper. Do you remember how many degrees the straight angle is? Cut out the hexagon and place it on the straight line. Place one triangle on the outside of the hexagon. We know that the angle of the triangle is 60º so we can determine the measurement of the hexagon angle by subtracting 180º - 60º = 120º. The measurement of the internal angle of the hexagon is 120º.

Other Measurements of the Pattern Blocks Do you know the measurement of the angles in the square? Remember they are right angles. Let’s find out the measurement of the diamond. How many of these pattern blocks will it take to total the 60º angle of the triangle? (Match up the points of the diamonds with the point of the triangle). Since you need two of these, what is the measurement of the angle in the diamond?

Other Measurements of the Pattern Blocks Can you find the measurement of the angles in the rhombus? Can you find the measurement of the angles in the trapezoid? What pattern blocks did you use?

Work with a partner to complete pages 428 and 429 in your book. More Practice Work with a partner to complete pages 428 and 429 in your book.

Lesson Wrap Up In this lesson, you learned how to use unit angles and fractions to find angle measures. How many different combinations can you come up with using the pattern blocks to total 180º? Homework (16-4 Practice) for one “Paw Signature” and (16-4 Reteaching & Practice) if you want two “Paw Signatures.” Website for Practice: http://www.mathplayground.com/geometry_quiz.html