Lesson plan

# Relationships of angles (IM Grade 7, Unit 6, Lesson 1)

teaches Common Core State Standards 7.G.A.2 http://corestandards.org/Math/Content/7/G/A/2
teaches Common Core State Standards MP1 http://corestandards.org/Math/Practice/MP1
teaches Common Core State Standards 7.G.B.5 http://corestandards.org/Math/Content/7/G/B/5

# Relationships of angles (IM Grade 7, Unit 6, Lesson 1)

Learning goals:

• Explain reasoning using informal language.
• Add and subtract angles that form 360 degree, straight and right angles.

Learning goals (Student facing):

• Let's examine some special angles.

Required materials:

• scissors
• blank paper
• pattern blocks
• straightedges
• protractors

Required preparation:

• Prepare sets of pattern blocks, one for each group of 3-4 students, consisting of at least 3 yellow hexagons, 6 green triangles, 6 orange squares, and 6 tan rhombuses.
• Cut blank paper in half so that each student can have 2 half sheets of paper.
• Prepare to distribute scissors, straightedges, and protractors.

Lesson Description

Students were introduced to angles in grade 4, when they drew angles, measured angles, identified angles as acute, right, or obtuse, and worked with adding and subtracting angles. Earlier in grade 7, students also touched on angles briefly in their work with scale drawings; however, this lesson begins a more detailed study of angles.

In this lesson, students gain hands-on experience composing and decomposing angles. They refresh their memory of 360∘, 180∘, and 90∘ angles, and they investigate angles that add up to those measures in preparation for being fomally introduced to complementary and supplementary angles in the next lesson.

Students see that not only addition and subtraction, but also multiplication and division, can be used when solving for unknown angles. There are many different ways to combine the angles on the pattern blocks and different ways to represent these combinations with equations, which encourages students to compare different solution methods and double-check their answers (MP1).