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## Class 8

### Course: Class 8>Unit 6

Learn to identify quadrilaterals such as kites, trapezoids, parallelograms, rhombuses, rectangles, and squares by side length, presence of parallel sides, and angle type. Created by Sal Khan.

## Want to join the conversation?

• upvote pls! help me earn a badge! • Is a square always a rombus? • Yes, because a rhombus is a parallelogram with equal sides, and a square is also a parallelogram with equal sides.

The difference is that the square also has four right angles.

Rhombus
- 4 equal sides
- parallelogram

Square
- 4 equal sides
- parallelogram
- 4 equal 90° angles

Notice that the square - by definition - always meets the criteria for a rhombus. So every square is also a rhombus!

However, not every rhombus is a square: if the rhombus has 2 acute angles and 2 obtuse angles, then it is just a rhombus.

Hope this helps!
• ༎ຶ‿༎ຶ im fine ༎ຶ‿༎ຶ • is there any proof that if a parallelogram has one right angle, it's a rectangle? • Well, the definiton of parallelogram is that both pairs of sides are parallel - what I mean by pairs of sides is tricky to explain without a drawing, so I'm gong to assume you already know it. The diefinition of right angle is a measure of 90 deg, which means the two lines are perpendicular to each other. So with some logic you can see that if one line a is perpendicular to line b, and line c is parallel to line a, then line b has to be perpendicular to c as well. Right? And that means the angle between b and c has to be a right angle as well. You can keep going around the parallelogram and get four right angles, which means it's a rectangle  • What is the type of this quadrilateral?
Be as specific as possible with the given data.
So it clearly is a quadrilateral.
We have four sides here.
And we see that we have two pairs of parallel sides.
Or we could also say there are two pairs of congruent sides
here as well.
This side is parallel and congruent to this side.
This side is parallel and congruent to that side.
So we're dealing with a parallelogram.
Let's do more of these.
So here it looks like a same type of scenario
we just saw in the last one.
We have two pairs of parallel and congruent sides,
but all the sides aren't equal to each other.
If they're all equal to each other,
we'd be dealing with a rhombus.
But here, they're not all equal to each other.
This side is congruent to the side opposite.
This side is congruent to the side opposite.
That's another parallelogram.
Now this is interesting.
We have two pairs of sides that are parallel to each other,
but now all the sides have an equal length.
So this would be a parallelogram.
And it is a parallelogram, but they're
saying to be as specific as possible with the given data.
So saying it's a rhombus would be
more specific than saying it's a parallelogram.
This does satisfy the constraints
for being a parallelogram, but saying it's a rhombus
tells us even more.
Not every parallelogram is a rhombus,
but every rhombus is a parallelogram.
Here, they have the sides are parallel to the side opposite
and all of the sides are equal.
Let's do a few more of these.
What is the type of this quadrilateral?
•Current transcript segment: Be as specific as possible with the given data .
So we have two pairs of sides that are parallel,
or I should say one pair.
We have a pair of sides that are parallel.
And then we have another pair of sides that are not.
So this is a trapezoid.
But then they have two choices here.
They have trapezoid and isosceles trapezoid.
Now an isosceles trapezoid is a trapezoid
where the two non-parallel sides have the same length, just
like an isosceles triangle, you have
two sides have the same length.
Well we could see these two non-parallel sides do not
have the same length.
So this is not an isosceles trapezoid.
If they did have the same length, then
we would pick that because that would
be more specific than just trapezoid.
But this case right over here, this is just a trapezoid.
Let's do one more of these.
What is the type of this quadrilateral?
Well we could say it's a parallelogram
because all of the sides are parallel.
But if we wanted to be more specific,
you could also see that all the sides are the same.
So you could say it's a rhombus, but you
could get even more specific than that.
You notice that all the sides are
intersecting at right angles.
So this is-- if we wanted to be as specific as possible-- this
is a square.
Got it right. • What is a kite? • What is a trapezoid and isosceles trapezoid?  