# Thread: area and perimeter of parallelogram

1. ## area and perimeter of parallelogram

hi,

i have a parallelogram which is made up of of co ordinates which are, A(2,1) B(8.9) C(12,9) D(6,1):

i have drawn the shape but i don't know how to work out the area and perimeter of it so i was looking for some help please.

thanks!

2. Originally Posted by andyboy179
parallelogram which is made up of of co ordinates which are, A(2,1) B(8.9) C(12,9) D(6,1)
Area is $\displaystyle \text{base}\times\text{height}$.
The base is $\displaystyle \overline{AD}$. What is the height?

3. would the base = 4? because on the grid it is 4 block long?
the height is not stated thats why im having problems.

4. The perimeter is easy- it is twice the size of the lengths of two adjacent sides. AB and AD are two such sides: their lengths are $\displaystyle \sqrt{(8- 2)^2+ (9- 1)^2}$ and $\displaystyle \sqrt{(6- 2)^2+ (1-1)^2}$.

The area of a parallelogram is "height times base". Fortunately two of the parallel sides are "horizontal"- parallel to the x-axis. The length of the base AD is the difference in x coordinates of A and D:6- 2= 4. The height is the difference in y-coordinates: 9- 1= 8.

5. Originally Posted by andyboy179
would the base = 4? because on the grid it is 4 block long?
the height is not stated thats why im having problems.
Yes, the base is 4 units. How far is the point $\displaystyle B$ from $\displaystyle \overline{AD}~?$

6. Originally Posted by HallsofIvy
The perimeter is easy- it is twice the size of the lengths of two adjacent sides. AB and AD are two such sides: their lengths are $\displaystyle \sqrt{(8- 2)^2+ (9- 1)^2}$ and $\displaystyle \sqrt{(6- 2)^2+ (1-1)^2}$.

The area of a parallelogram is "height times base". Fortunately two of the parallel sides are "horizontal"- parallel to the x-axis. The length of the base AD is the difference in x coordinates of A and D:6- 2= 4. The height is the difference in y-coordinates: 9- 1= 8.
would the perimeter be 70 and 4?

7. Originally Posted by Plato
Yes, the base is 4 units. How far is the point $\displaystyle B$ from $\displaystyle \overline{AD}~?$
90 degrees?

8. Originally Posted by andyboy179
would the perimeter be 70 and 4?
The perimeter is a single number!

9. Originally Posted by andyboy179
90 degrees?
90 degrees measures an angle, not a distance!

10. Originally Posted by HallsofIvy
The perimeter is a single number!
would i just add them together?

11. Originally Posted by HallsofIvy
90 degrees measures an angle, not a distance!

okay. would it be 13

12. can someone confirm if this is correct so far?

13. Plato or Hallsofivy for the area would I do 4 x 13=52???

14. ## area and perimeter of parallelogram

Hi andyboy179,
You have drawn this shape on a grid and you should be able to find the lengths of the sides and you id a 4. So what is the length of a longer side,With this the perimeter is easy. Just add the four sides.You may be hung up on area so go back to your book or to internet to find out how to calculate area.The numbers are right there on your grid.

bjh

15. Would the area be:
4x8=32?
also for the perimeter would I just do 4+4+8+8=24?

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