Interesting perimeter and area problems | Perimeter, area, and volume | Geometry | Khan Academy

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Three example problems involving perimeter and area
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Geometry on Khan Academy: We are surrounded by space. And that space contains lots of things. And these things have shapes. In geometry we are concerned with the nature of these shapes, how we define them, and what they teach us about the world at large--from math to architecture to biology to astronomy (and everything in between). Learning geometry is about more than just taking your medicine ("It's good for you!"), it's at the core of everything that exists--including you. Having said all that, some of the specific topics we'll cover include angles, intersecting lines, right triangles, perimeter, area, volume, circles, triangles, quadrilaterals, analytic geometry, and geometric constructions. Wow. That's a lot. To summarize: it's difficult to imagine any area of math that is more widely used than geometry.
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[@karlzander5389]

I hate math, but sometimes I love math...idk why. Is it just me or?

[@teeviya1056]

Your not alone Same here

[@superdau]

@Threatter No, you are wrong. You are assuming things from a drawing, which is a very bad thing to do. Where is it claimed that for example EFGB are on one line? Angles are not used and not needed in this example at all.

[@AshleyBas10]

@Threatter the angles arent mentioned at all, they can easily be different angles and different length sides, it is just total perimeter given

[@ThomasGiles]

The last problem... From the diagram, it's not shown that the "other" 2 side is 2 in length. Other than that, great video!

[@DeeDee-oi1xz]

2:28 " ...and we're done". I wish it seemed that easy to me.

[@thecosmos7671]

Late but,let's see if I can help. So , basically in the star we only have to measure the perimeter of the star " ⭐" and not what lies inside so the outer perimeter will do

[@TarakKakkar]

@@thecosmos7671 4 years late.

[@tejasshelar2674]

great work

[@srjz]

Your the best thanks for teaching us

[@matthewkatigbak9876]

CONGRATS ON 3 MILLION!!!

[@shadenowo5276]

Thanks

[@threatter1676]

The answer to the first problem (the star) is wrong. The angle of the pentagon is 108°, therefore the angle in the triangle must be 180° - 108° = 72° The perimeter of FGHIJ is 50, so the length of FG is 10. If the perimeter of AGF is 30, then the length of AF and AG must be 10. This means that the triangle is equilateral, all angle must bee 60°. So to sum up: The correct answer is that the problem is unsolvable. Your answer is incorrect.

[@sami4824]

THat Part

[@wolfey5733]

why are there only 25 comments

[@krishnagutta5607]

what program are you using?

[@DigitalPsyops16]

I realise in three years this hasn't popped back into your mind one time, but Sal uses Smoothdraw. It's a free program.

[@SirArghPirate]

5*30-50=100

[@bigk2367]

I am the newest here 😎

[@juicepanda2956]

hello random person at the top of the comment section

[@GearZNet]

@JNanu34 College... :/

[@mohiniwalke7574]

Jshf