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### Unit 5: Lesson 4

Topic D: Drawing, analysis, and classification of two-dimensional shapes

There are many different relationships between the types of quadrilaterals. Parallelograms have two sets of parallel sides, rhombuses are parallelograms with equal side lengths, and squares are rhombuses with right angles. Though there is overlap, not all quadrilaterals fit into each category. Created by Sal Khan.

## Want to join the conversation?

• If quad means four, what means five?
• Pent means five like the pentagon it has five sides.
• So let me get this straight, Rhombi are squares because they both have sides of equal length, Quadrilaterals are not rhombi because a quadrilateral can be many different shapes and it is not a parallelogram for the same reason, a parallelogram can be other things. Right? Do I have that correct? Please Answer, thanks.
• Rhombi are not all squares, but squares are all rhombi, just like all rhombi are quadrilaterals but not all quadrilaterals are rhombi. A square is just a more specific type of rhombus, just like a rhombus is a more specific type of square. It's just like fish are all animals (unless they're toys) but not all animals are fish.
• At -, did he also mean to say that all sides are of equal length? A rectangle is also a quadrilateral with only 90-degree angles, but all the sides aren't always the same length.

UPDATE (Mar. 8, 2021): Since a rhombus has sides of equal length, Sal already implied that when bringing up the square. I fully understand now!
• Yes, rhombus is a quadrilateral with 4 sides of equal length. So rectangles are not always rhombus.
• a square is always a rhombus
• Of course it really is. A square has the same identities of a rhombus.
• how can a parallelogram and quadrilateral not always be a rhombus? Can someone explain.
• In word problems, be careful not to assume that a quadrilateral has parallel sides or equal sides unless that is stated. A parallelogram has two parallel pairs of opposite sides. A rectangle has two pairs of opposite sides parallel, and four right angles. ... No, because a rhombus does not have to have 4 right angles.
• How do I make my character grow
• You do the test after the video and then you get points or something then your thing grows!
• how long has the name ''square'' been around?
• That's a really good question. but, unfortunately, I don't know.
• Is impossible to tarigle is has4side