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 Post subject: Geometry pg.62, #32Posted: Fri Jun 17, 2011 9:53 pm

Joined: Thu Feb 10, 2011 11:12 pm
Posts: 10
I understand why the Pythagorean Theorem was used, but I don't understand where they are getting 192/2 = 361/2? or 212/2 = 441/2? Please explain.

I understand that 19^2 = 361 & 21^2 = 441. And then divide that by 2 to get the area in sq. in. and then finally find the difference b/w the two.

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 Post subject: Re: Geometry pg.62, #32Posted: Sat Jun 18, 2011 4:10 am

Joined: Thu Feb 12, 2009 6:32 pm
Posts: 497
21 inch screen:

x^2 + x^2 = 21^2

2*x^2 = 21^2

x^2 = (21^2)/2 .... this is the area of the screen (the square of a side is the area)

19 inch screen:

(19^2)/2

difference: (21^2)/2 - (19^2)/2

Veritas Help

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 Post subject: Re: Geometry pg.62, #32Posted: Thu Jun 23, 2011 10:03 pm

Joined: Thu Feb 10, 2011 11:12 pm
Posts: 10
Thanks for the reply, but I already understand that process. I'm not getting where they get 212/2 = 441/2 or 192/2 = 361/2. Where is the 212 & 192 coming from?

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 Post subject: Re: Geometry pg.62, #32Posted: Sat Jun 25, 2011 6:40 pm

Joined: Thu Feb 12, 2009 6:32 pm
Posts: 497
If the diagonal is 21 inches, we have an isosceles right triangle as follows:

x^2 + x^2 = 21^2, where x is a side of the square.

2 * x^2 = 21 * 21

x^2 = (21*21)/2 ... but since x is a side, side * side = area, so x^2 = area of the square

- Veritas Help

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