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## Get ready for 8th grade

### Course: Get ready for 8th grade > Unit 4

Lesson 2: Polygons on the coordinate plane- Drawing a quadrilateral on the coordinate plane example
- Drawing polygons with coordinates
- Area of a parallelogram on the coordinate plane
- Area and perimeter on the coordinate plane
- Coordinates of a missing vertex
- Example of shapes on a coordinate plane
- Dimensions of a rectangle from coordinates
- Coordinates of rectangle example
- Quadrilateral problems on the coordinate plane
- Quadrilateral problems on the coordinate plane
- Parallelogram on the coordinate plane

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# Coordinates of rectangle example

CCSS.Math:

Sal solves a challenging problem involving a quadrilateral on the coordinate plane.

## Want to join the conversation?

- This is confusing and counter-intuitive but maybe that's a good thing because it forces you to correctly associate the x/y axes with the 2 values in an ordered pair.

I used a, b and c instead of x, y and z to make this easier to understand.(10 votes)- Yeah, they should have done that too. Good thinking!(1 vote)

- why does x go first instead of y(5 votes)
- With a coordinate grid, the horizontal direction, or "axis" is called the x axis. The vertical direction, or axis, is called the y axis. In ordered pairs, the things in parentheses that tell you what point it's referring to, the x axis is always the first number, probably because it's first in the alphabet.(4 votes)

- So is this like a number swapping place to place(5 votes)
- How do you find the length of a shape with coordinates.(4 votes)
- Find the distance between two points. So in this video, we end up with (2, 7) and (2, 3). This distance between 3 and 7 is 4, so we know the side between those two points has a length of 4.(3 votes)

- here's a link to help https://www.khanacademy.org/math/early-math/cc-early-math-counting-topic but I hope this is helpful(4 votes)
- yeah like y anm hrh fhhbfr brfhbdr(3 votes)
- why does x go first instead of y(3 votes)
- How can we do this with a parallelogram though(2 votes)
- parallelogram has two pairs of parallel sides. A rectangle is a parallelogram, the math for both is the same. A rhombus and a square are also parallelograms(1 vote)

- he didnt even get done with the question(2 votes)
- THE VERTICES OF A RECTANGLE ARE A(4,6), B(4,-1), C(0,-1)< D(0,6) what are the dimensions of the rectangle?(2 votes)
- In this case the dimensions of the rectangle is 5×7.(1 vote)

## Video transcript

- [Voiceover] So I've copied
and pasted this question from the exercises on Khan Academy. It says, "Sort the following expressions "from least to greatest
based on the coordinates "of the rectangle below." So we need to figure out
would y, z and x are. Then we assort them. So let's first look at, well let's look at y. And this is a little bit counter intuitive because they're using the variable y to represent the x-coordinate, to represent the x
coordinate of this point. So let's see if we can figure out what the x-coordinate of this point is. Well it's a rectangle. The x-coordinate of this
point right over here, it's going to be the same as
the x-coordinate of this point. They sit on the same vertical line the way that it is drawn. So if this has an
x-coordinate of x equals four, then this is going to have
an x-coordinate of four. And now we use a variable
y for the x-coordinate which is a little strange but this is going to be
the point four comma seven. So y is equal to four. Now let's see what we
can figure out about z. Well, z is the y coordinate for, let me use another color here, z is the y coordinate for this point. Now, what other point has
the same y-coordinate? Well, it's going to be at the same level, I guess you could say, in the vertical direction. It's going to sit on the
same horizontal line. So it's going to have the same
y-coordinate as this point. Now this point has a
y-coordinate of three. So this point, it's y-coordinate
is going to be three or we could say that z is equal to three. So this is going to be equal to three. And then last but not least, we need to figure out what x is. And x is the x-coordinate. Let me do this in another color. X is the x-coordinate for this point. Well, this x-coordinate is
going to be the same thing as the x-coordinate for this point up here which is equal to two. They sit on the same vertical line. They both sit on the line, x equals two. And so x is going to be two. It is the x-coordinate and
it's also the variable x. So this is going to be two. So if we want to sort them
from least to greatest, x is the least. Then we would go, it's
actually the exact opposite of what we have here. The x then z, then y. Two then three, then four. So actually, let me get the exercise out and just check our answer. So x is the least then z is in the middle and then y is the largest. We can check our answer. We got it right.