Sort shapes by parallel sides and right angles
Sorting shapes by their features teaches your child to look for evidence instead of judging by appearance, a way of thinking that reaches well beyond geometry. It is also why a square counts as a rectangle. In 5th grade they build a family tree of shapes, learning that every square is a rectangle and every rectangle is a parallelogram, and in middle school these features help them find areas and angles.
In this video, your child will learn to sort shapes by parallel sides and angles.
The lesson stops at each question for your child's answer.
Three problems, each a little harder
Each problem is worked step by step. Your child will solve the last one before Bobby shows how.
Example 1
How many right angles does the new shape have?
Example 2
How many pairs of parallel sides does this trapezoid have?
Your child's turn
What kind of triangle is this?
The three key steps
- 1A right angle: a square corner
- 2Parallel sides never meet
- 3Right triangle: 1 right angle
Mistakes to listen for
- Deciding a triangle is not a right triangle because it is turned so the square corner is not at the bottom.
- Leaving a square out of the group with parallel sides or right angles, because it already has its own name.
- Calling two sides parallel because they look close, without checking that they stay the same distance apart.
The lesson shows every step, so your child sees why it works. Read our parent's guide to sorting shapes by their sides and angles →
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More 4th grade Geometry, with questions your child answers along the way.
Questions parents ask
Does my child need an account to watch?
No. You can watch this on any device at any time. If your child would like to practice sorting shapes by their sides and angles, and you'd like parent-friendly reports on your child's progress and growth, you can join Bobby's Math Club for unlimited free practice.
What happens when my child answers a question?
A right answer gets a cheer, and the lesson carries on. If your child isn't sure, they can tap "I don't know yet", and Bobby gives the answer and shows another example. Nothing is scored or stored.
Is this the same lesson that's on YouTube?
Yes. Here, the lesson stops at each question and waits for your child to answer. On YouTube, each question stays on screen for a few seconds, and then the lesson plays on.
Where can I learn more?
There's a short, kid-friendly lesson like this one for every Pre-K to 5th grade math skill, all in our video library. Our parent's guide to sorting shapes by their sides and angles has more on where kids get stuck and how you can help at home. In the club, your child practices at just the right level, about five minutes a day, and you get parent-friendly reports as they grow. Learn more about how it works →
Practice sorting shapes by their sides and angles
Questions at your child's level, about five minutes a day, on sorting shapes by their sides and angles and whatever PK-5 skills they need to develop. Unlimited practice, free forever.
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