i-Ready Classroom Mathematics Grade 4, Unit 6: Geometry and Angles
In this unit, your child finishes the year with geometry. They identify points, lines, rays, and angles; classify shapes by parallel and perpendicular sides; and find lines of symmetry. They also learn how degrees measure angles, use a protractor, and add angles to find unknown measures. It follows the measurement and data unit.
By Robert “Bobby” BarnettMath teacher, parent, and founder of Bobby’s Math Club
What is my child learning in Unit 6?
- Explaining that angles are measured by how far one ray turns from the other, out of a full 360-degree circle. Learn more: What angles are and how degrees measure them
- Using a protractor to measure angles to the nearest degree and to draw angles of a given measure. Learn more: Measuring and drawing angles with a protractor
- Finding unknown angle measures by adding or subtracting, when a larger angle is split into smaller angles that don't overlap. Learn more: Adding angles together to find a missing one
- Recognizing points, lines, line segments, rays, and angles, and drawing parallel and perpendicular lines. Learn more: Spotting lines, rays, angles, and parallel lines
- Classifying triangles and quadrilaterals by their sides and angles, using sorting diagrams and rules. Learn more: Sorting shapes by their sides and angles
- Identifying line-symmetric shapes and drawing all of their lines of symmetry. Learn more: Finding lines of symmetry
Sample questions to try together
These are real questions from our practice. Tap the speaker to hear one read aloud, or the light bulb for a hint, and talk about the answer together.
Question 1 of 3
An angle measures 60°. How many one-degree angles does it turn through?
- 300
- 60
- 6
How you can help
- Look for right angles on a walk, in windows, signs, and sidewalk squares. Ask your child to find an acute and an obtuse angle too, and explain how they know.
- Open a laptop or a book to different angles. Have your child guess each one in degrees, then use the corner of a sheet of paper to check whether it's more or less than 90.
- Cut a square and a long rectangle from scrap paper. Ask your child to fold each every way the halves match, and count the lines of symmetry: 4 and 2.
Where kids can get stuck
- Overlooking a right angle when a shape is tilted, because its corner isn't lined up with the page.
- Adding the whole angle to its parts, and giving an answer bigger than the whole.
- Recording 130 degrees for an angle clearly narrower than a square corner.
Practice makes perfect
Bobby's Math Club has practice problems that adapt to your child’s level, each with a detailed explanation and an easy-to-follow video, so your child can build confidence in these skills one step at a time.
Words your child will hear
- point
- An exact spot, shown with a dot and named with a capital letter.
- ray
- A part of a line that starts at one point and goes on forever in one direction.
- angle
- The figure made by two rays that share an endpoint.
- degree
- The unit for measuring angles; a full turn is 360 degrees.
- protractor
- A half-circle tool marked in degrees, used to measure and draw angles.
- parallel lines
- Lines that always stay the same distance apart and never meet.
- perpendicular lines
- Lines that meet or cross to make right angles.
- classify
- To sort shapes into groups by what they have in common.
- line of symmetry
- A line that folds a shape into two halves that match exactly.
Ready to build your child’s confidence with geometry and angles?
In Bobby's Math Club, your child practices these skills at just the right level, with a hint when they need one, a clear explanation after every question, and kid-friendly videos. Unlimited practice is free.
Join the club
Written by Robert “Bobby” Barnett
Bobby is an award-winning math teacher, the author of Meet Every Learner’s Needs, and the father of two elementary-school math learners. He uses Bobby’s Math Club with his own kids a few times every week. Learn more or contact Bobby.
Which math standards does i-Ready Classroom Mathematics Grade 4 Unit 6 cover?
i-Ready Classroom Mathematics Grade 4 Unit 6 covers these math standards. Each one links to what it means, sample questions, and teaching strategies.
- 4.MD.C.5: Understand angles as turns measured in degrees: a full turn is 360°.
- 4.MD.C.6: Measure angles in degrees with a protractor.
- 4.MD.C.7: Add angles together, and find a missing angle.
- 4.G.A.1: Name rays and angles, and spot parallel and perpendicular lines.
- 4.G.A.2: Sort shapes by their parallel sides and right angles.
- 4.G.A.3: Find lines of symmetry, where a shape folds into matching halves.
For teachers: Unit names and order vary between editions and districts, so your school’s own materials have the exact sequence. Learn how Bobby's Math Club can help your students grow.