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Lesson 4: Multiply to find area

Counting unit squares to find area formula

Sal uses unit squares to see why multiplying side-lengths can also find the area of rectangles.    Created by Sal Khan.

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• Does it matter if it's a rectangle or a square in area? Wouldn't it still be length times width?
• That's true. The only thing is, when calculating the area of a square, you can simply multiply one of the sides by itself, since you know the other sides are all the same.
• Could I use this information for inches as well?
• Yeah. If you do the same thing, but change the measurement, you can do the same thing for inches like you did with meters.
• Hi Khan, My name is Wyatt and I live in Vancouver British Columbia. I hope that all of Khan is well during this crazy time of CV19. I have a math/space problem that needs solving. I am hoping that you would kindly help me out. I own a yoga studio in Vancouver. The province is slowly letting small businesses open with restrictions. I am measuring the studio space later today and will have accurate numbers of what the square footage of the floor space is. What i need to do in the space to make it safe is go from a capacity of 100 people to 29 people. So, I need to fit 29 yoga mats in this space in an off center pattern. For example - the lay out would look like the off set dots on a dice of 5 dots. That pattern would be repeated within the space to make up 29 spaces or 29 yoga mats at equal distance apart. If I send you a drawing of the space would you be able to reconfigure the space to accommodate 29 yoga mats. I will also provide the size of the Yoga mat. What do you think of this ? Is there an instructor out there that can connect with me and help me solve this spacial math problem.
• you must have peace in your house cause my house is 0% peaceful and only peaceful when my dad takes me on hikes or nature walks
• how do people know the perimeter of a circle? I'm confused..
• The perimeter of a circle is called the circumference. It is π multiplied by the diameter of the circle. And since the diameter is twice the radius, you could also say that C=πd=2πr. If you want to approximate π, use 3.14
• how do you write with your mouse? it's so cool!
• what is 1000 times 1000=10000
• 1 million
• can i use this information for finding area in triangles?
• No, you use area by multiplying base times height, then divide by 2 by using square units.