GRE Math | Geometry Secret Shortcut

[@pratyushtripathy2750]

I solved a problem this morning while practising, and used the Pythagoras theorem twice to get the inner diagonal of the cube. And here you are with a shortcut. Thanks man!

[@davidblainex14]

is it always always gonna be multiplied by sqrt 3 or do u multiply it by whatever it says on the comparison

[@foodtechsimplified]

Chris: Talking about Maths rather than English Me: Wait that's illegal! :P By the way, we missed you, Chris!!!

[@OPENINSTRUCTION]

Nice explanation, Chris! Thank you :)

[@liddojellybean0506]

Chris is my fav

[@ashishsinha9035]

Thanks Chris!

[@MagooshGRE]

We're so glad you like the video!

[@vivisanchez4408]

How can we tell it is a cube?

[@ishaankakkar522]

Won't the diagonal be greater since it is a cube and not a square and A and B are on the opposite ends of the cube?

[@whereswaldo1376]

No. If you don't believe him, you can even derive the sqrt(3) yourself. Draw the diagonal from A to B and then draw a triangle with the same diagonal as the hypotenuse. We know the diagonal of a square is sqrt(2), so (sqrt(2))^2 + 1^2 = c^2. solve for c and you get sqrt(3). So, the hypotenuse (or diagonal AB) is sqrt(3).

[@pratyushtripathy2750]

Yeah, that's what he is saying. Root 3 is somewhere around ~1.73, which is more than 1. Diagonal of a square with side 1 would be root 2 (~1.41), which is also greater than 1.

[@arandomstrangerontheintern3581]

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