Reveal Math Grade 5, Unit 11: Geometry
In this unit, your child classifies two-dimensional shapes by their properties: parallel sides, equal sides, and right angles. They see that shapes fit inside larger families, so a square is a special rectangle and a special rhombus, and every rectangle is a parallelogram. It follows the fraction units and leads into coordinate geometry, where shapes meet the coordinate grid.
By Robert “Bobby” BarnettMath teacher, parent, and founder of Bobby’s Math Club
What is my child learning in Unit 11?
- Reasoning that a shape has every property of the categories it belongs to, so a square has all the properties of a rhombus. Learn more: Why a square is also a rectangle
- Drawing a family tree of quadrilaterals by their sides and angles, from quadrilaterals to parallelograms to rectangles, rhombuses, and squares. Learn more: Sorting four-sided shapes into a family tree
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
Ines sorts tiles. She knows every rhombus has four sides of the same length. Which tile must also have four sides of the same length?
- A parallelogram tile
- A square tile
- A rectangle tile
How you can help
- Hunt for quadrilaterals on a walk or ride, like windows, doors, and tiles. Ask your child for every name each shape could have and what makes each one fit.
- Play 'Who am I?' with clues like 'I have 4 equal sides and 4 right angles.' Ask your child to name all the families the shape belongs to.
- Turn a square sticky note or coaster onto its corner. Ask whether it is still a square, and talk about why turning a shape never changes its name.
Where kids can get stuck
- Reversing the reasoning, so because squares have four equal sides, they say all rectangles do too.
- Forgetting that a rectangle is a parallelogram, so its parallel, equal opposite sides come as a surprise.
- Calling every slanted four-sided shape a rhombus, without checking that all four sides are equal.
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
- quadrilateral
- Any closed flat shape with 4 straight sides.
- parallelogram
- A quadrilateral with two pairs of parallel sides.
- rectangle
- A parallelogram with 4 right angles.
- rhombus
- A parallelogram with 4 equal sides.
- square
- A quadrilateral with 4 equal sides and 4 square corners.
- trapezoid
- A quadrilateral with a pair of parallel sides.
- right angle
- A square corner, like the corner of a sheet of paper.
- parallel
- Lines that stay the same distance apart and never meet.
- property
- A feature that every shape in a group has, like 4 equal sides.
Want to help your child master classifying shapes?
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.
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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 Reveal Math Grade 5 Unit 11 cover?
Reveal Math Grade 5 Unit 11 covers these math standards. Each one links to what it means, sample questions, and teaching strategies.
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.