Into Math Grade 4, Unit 5: Geometry and Measurement
In this unit, your child names and draws lines, rays, and angles; sorts shapes by parallel and perpendicular sides; and learns that angles are measured in degrees. They also convert between units of measure and use area and perimeter formulas for rectangles. It follows the fraction and decimal work and closes out the year.
By Robert “Bobby” BarnettMath teacher, parent, and founder of Bobby’s Math Club
What is my child learning in Unit 5?
- Identifying and drawing points, lines, segments, rays, angles, and parallel and perpendicular lines, both on their own and inside shapes. Learn more: Spotting lines, rays, angles, and parallel lines
- Classifying triangles and quadrilaterals by their parallel sides, perpendicular sides, and right, acute, or obtuse angles. Learn more: Sorting shapes by their sides and angles
- Converting larger units to smaller ones in the same system, such as 3 feet to 36 inches or 2 hours to 120 minutes. Learn more: Converting feet to inches and kilograms to grams
- Finding the area and perimeter of rectangles with formulas, and working backward to find a missing side length. Learn more: Using area and perimeter to solve real problems
- Understanding that an angle is measured in degrees as part of a full 360-degree turn, so a right angle is 90 degrees. Learn more: What angles are and how degrees measure them
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
How many endpoints does a line segment have?
- Two
- One
- Zero
How you can help
- Measure a room or a rug with a tape measure, then ask your child to find its perimeter, its area in square feet, and its length in inches.
- Convert time together: if a movie runs 2 hours, ask how many minutes that is, and then how many seconds are in 3 minutes.
- Look for shapes on a walk or ride, such as street signs, windows, and tiles, and ask whether each has parallel sides, right angles, or both.
Where kids can get stuck
- Dividing instead of multiplying when converting to a smaller unit, ending up with fewer inches than feet.
- Adding only two sides of a rectangle for the perimeter, getting 13 feet for an 8-by-5 rectangle instead of 26.
- Thinking perpendicular lines must run straight up and across, and missing them when they are tilted.
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
- ray
- Part of a line with one endpoint that goes on forever in one direction.
- line segment
- Part of a line with two endpoints.
- parallel lines
- Lines that stay the same distance apart and never meet.
- perpendicular lines
- Lines that cross or meet to form right angles.
- degree
- The unit for measuring angles; a full turn is 360 degrees.
- convert
- To change a measurement to a different unit, like 3 feet to 36 inches.
- area
- The amount of space inside a flat shape, measured in square units.
- perimeter
- The distance all the way around a flat shape.
- formula
- A rule written with letters, such as area = length × width.
Want to help your child master geometry and measurement?
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 Into Math Grade 4 Unit 5 cover?
Into Math Grade 4 Unit 5 covers these math standards. Each one links to what it means, sample questions, and teaching strategies.
- 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.MD.A.1: Change larger units into smaller ones, like 4 feet = 48 inches.
- 4.MD.A.3: Solve problems with the area and perimeter of rectangles.
- 4.MD.C.5: Understand angles as turns measured in degrees: a full turn is 360°.
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.