enVision Mathematics Grade 4, Topic 16: Lines Angles and Geometric Measurement
In this unit, your child uses formulas to find the area and perimeter of rectangles and solves real problems with them, like how much fencing a playground needs. They also work backwards to find a missing side. It closes the year by connecting the measuring work from the angle unit to the space inside and around shapes.
By Robert “Bobby” BarnettMath teacher, parent, and founder of Bobby’s Math Club
What is my child learning in Topic 16?
- Using area = length × width and the perimeter formula for rectangles, and finding a missing length from a known area or perimeter. Learn more: Using area and perimeter to solve real problems
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
Sofia makes a square picture frame. The perimeter of the frame is 64 inches. How long is each side of the frame?
- 16 inches
- 256 inches
- 32 inches
How you can help
- Measure a placemat or book cover with a ruler, say 12 by 9 inches. Have your child find the perimeter, 42 inches, and the area, 108 square inches, and say which one a ribbon border needs.
- Count the tiles on a floor or patio. Ask your child to find the area by multiplying rows by columns, then count a few rows to check.
- Ask a missing-side question about a rug. If it covers 24 square feet and is 4 feet wide, how long is it? Then ask how much trim would go around it.
Where kids can get stuck
- Mixing up area and perimeter, multiplying the sides when the question asks for the distance around.
- Adding only two sides for the perimeter, so a 6-by-4 rectangle gets 10 instead of 20.
- Writing a perimeter in square units, or an area in plain feet instead of square feet.
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
- area
- The space inside a flat shape, measured in square units.
- perimeter
- The distance all the way around a flat shape.
- formula
- A rule written with symbols, like area = length × width.
- square unit
- A square with sides 1 unit long, used to measure area.
- length
- How long something is from end to end.
- width
- How wide something is from side to side.
Ready to build your child’s confidence with perimeter and area?
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 enVision Mathematics Grade 4 Topic 16 cover?
enVision Mathematics Grade 4 Topic 16 covers this math standard. Each one links to what it means, sample questions, and teaching strategies.
- 4.MD.A.3: Solve problems with the area and perimeter of rectangles.
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.