Lesson 4

Measuring and Estimating Angles

Est. Class Sessions: 1–2
X

Mathematical Standards

4.MD.C
Geometric measurement: understand concepts of angle and measure angles. (4.MD.C.5, 4.MD.C.6, 4.MD.C.7)

Standards for Mathematical Practice

MP1.
Make sense of problems and persevere in solving them.
MP2.
Reason abstractly and quantitatively.
MP3.
Construct viable arguments and critique the reasoning of others.
MP5.
Use appropriate tools strategically.
MP6.
Attend to precision.

Students estimate angle measures using benchmarks. They also measure and draw angles using protractors.

Content in this Lesson

  • Identifying acute, obtuse, right, and reflex angles using angle measures [E2].
  • Estimating the size of an angle using 90°, 180°, and 360° as benchmarks [E11].
  • Using a protractor to measure angles and draw to the nearest degree [E12].
  • Using addition and subtraction to find unknown angles [E1].

Daily Practice and Problems I–J

I. Angles and Time

J. Order of Operations

X

Materials for Students

Daily Practice and Problems Lesson Homework Assessment

Student Books

 Student Guide
Student Activity Book

Teacher Resources

 Teacher Guide - digital

Supplies for Students

Angle Sort Cards from Lesson 1 (stored in an envelope) or (Student Activity Book) Page 317
envelope
protractor
a square corner (a small sticky note or cardboard corner)
clear tape
blank paper

Materials for the Teacher

Display of the Angle Sort Cards from Lesson 1 (Student Activity Book) Page 317
Display of Math Practices (Student Guide) Reference
a square corner (a small sticky note or cardboard corner)
straws-and-paper-clip model for an angle from Lesson 1
Geometry Word Chart created in Lessons 1 and 3. See Materials Preparation.
chart paper to add to the Geometry Word Chart
clear protractor
Unit 9 Assessment Record

Materials Preparation

Angle Sort Cards. If you did not do so in Lesson 1, ask students to cut apart the cards on the Angle Sort Cards page in the Student Activity Book. Cards can be stored in an envelope.

Geometry Word Chart. Display the parts of the Geometry Word Chart created in Lessons 1 and 3. Students will refine their descriptions of the angle types in this lesson.

Assessment in this Lesson

Assessment Expectation Assessed Math Practices Expectation Assessed

Draw and Solve Problems with Angles
Check-In: Questions 8–16
Student Activity Book
Pages 326–328
E11.
Estimate the size of an angle using 90°, 180°, and 360° as benchmarks.
E12.
Use a protractor to measure and draw angles to the nearest degree.
MPE3.
Check for reasonableness. I look back at my solution to see if my answer makes sense. If it does not, I try again.
MPE6.
Use labels. I use labels to show what numbers mean.

Vocabulary in this Lesson