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Lesson 1: Area and perimeter

# Area & perimeter word problem: dog pen

Sal figures out the width of a dog pen. Created by Sal Khan.

## Want to join the conversation?

• How would you figure the area of a pentagon?
• you would find it by timeing all the sides and you will get your answer like you wanted.
• Lisa built a rectangular flower garden that is 4 feet wide and has a perimeter of 26 feet.
• First, you multiply the width by 2. The product is 8. Next, you subtract 8 from the perimeter which is 26, and the difference is 18. Afterwards, 18/2 = 9. This means that 9 is the length. If you want to figure out the area, just multiply 4 and 9, and the product is 36 feet squared.
• Is there another way of doing this?
For example, what I learned was 78/2 and then take that answer and subtract by the one length that the problem gives you, because the formula that I learned was 2(L+W).

And also, which is the fastest and easiest way of doing this??
• there is definitely many ways to solve the problem. the way you mentioned is one of them.
• How to calculate depth?
• Depth is not something that you would calculate so much as you would just measure it. You would need a starting place - something like sea level (the surface of the sea), then you would just measure down to the bottom to find depth.
• *What if they don't give you the length? And they just give you the area and height?*
• then if it was a square you could write the some on all the sides.
• i am going to up vote every single coment
• no you can't
• im stuc

The area of a square is 144 square centimeters.
What is the length of one side of the square?
• The area of a square is the side length times itself. So we need to find what positive number times itself would give 144. This positive number is 12. (This process is called taking the square root.)

The area is given in square centimeters, so the side length is in centimeters.

So the side length is 12 centimeters.
• how do you find the area of a cricle
• The formula is pi times the radius squared.
I hope this helped a bit!
Edit: Ask me if you need help :)