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### Course: Basic geometry and measurement > Unit 8

Lesson 1: Area of parallelograms# Area of parallelograms

Understand how to find the area of a parallelogram and why it works.

## Intuition for why the area of a parallelogram is $A=bh$

The formula for the area of a parallelogram is base times height, just like the formula for the area of a rectangle.

*But wait! Why are the formulas the same?*Look what happens when we slide part of the parallelogram to the right.

Genius! We made the parallelogram into a rectangle.

**Key intuition:**We can make every parallelogram into a rectangle, which is why we use the same formula to find the area of a parallelogram and a rectangle.

## Practice problem 1

## Practice problem 2

## Want to join the conversation?

- why does it not count when the number is curve(167 votes)
- If it was carved it can’t have a number(40 votes)

- Would it still work if it wasn't drawn to scale? Also, are you not just multiplying the numbers, or is there more to it?

Please explain in full terms.(57 votes)- Another way of thinking why it will work is that a Parallelogram has 2 pairs of sides that are of equal length (Opposite sides have equal length).

Therefore, the parallelogram will always be able to fit into a rectangle when rearranged properly => Formula of finding the area of a rectangle will work as long as we are sure that the figure that we are handling is truly a parallelogram irregardless of whether it is drawn to scale or not.(27 votes)

- How come they did not put a multiplication sign, they just put
*bh*? shouldn't there be multiplication sign?(8 votes)- putting bh is the same as b • h or b x h(71 votes)

- what is with the extra third number when practicing? like for example we are timesing the base and height (10 x 14 = 140) but there is a third number outside the parallelogram? we just basically ignore it?(15 votes)
- A third number will usually be measuring the length of one of the diagonal sides. I would have to see the specific example to be sure though.(17 votes)

- the formula is b × h=A right?(20 votes)
- yes and you can also watch the video again if you need some more help(7 votes)

- this is confusing(0 votes)
- if there will be only two numbers multiply those or act like the shape provided can be turned into a square then do it like it is a square.(14 votes)

- how do you figure out the area of a circle?(8 votes)
- pie2 times the diameter(8 votes)

- why don't you just multiply the length by the height(5 votes)
- you do, but the angled line isn't its height(6 votes)

- why is there a third number if we are just timing the base and height(7 votes)
- Hi,

That's an interesting question!

In many math tests and quizzes they often add a third number to a shape when we are calculating the area of the shape. The third number has nothing to do with the problem and is only there to confuse us.

I hope this helped!(6 votes)

- How come we weren't given an example with 3 numbers before being asked to solve for the area in the exercises?(6 votes)
- Because only two numbers need to be used: The base and the height. There can be an unneeded side length. GOOD LUCK ;)(4 votes)