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ghezas
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Guide 3-page 39 problem set #1

by ghezas Mon Jun 17, 2013 3:07 pm

So I'm having a really difficult time understanding the first problem set. I don't understand what an aspect ratio is or its relation the the 'diagonal"--or how to begin solving for area?
tommywallach
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Re: Guide 3-page 39 problem set #1

by tommywallach Wed Jun 19, 2013 10:43 am

Hey Ghezas,

"Aspect ratio" is defined right at the top of the page. It's the ratio of a screen's width to its height.

So draw this TV. The diagonal is 25, and the ratio of the two perpendicular sides of the resulting triangle are in a ratio of 4:3. That means we can just write 4x and 3x (if that step is unclear to you, read the Ratios chapter in our Word Problems book for more explanation). From there, you only need to use the pythagorean theorem (a^2 + b^2 = c^2) to solve for the two sides, and you can use the result to calculate the area.

Hope that helps!

-t
jrgarrigues
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Re: Guide 3-page 39 problem set #1

by jrgarrigues Mon Jun 24, 2013 9:30 pm

Ghezas might be talking about an error in the solution to problem #1 on page 39. The first sentence says:

"1. (A): For the TV in Quantity A, the aspect ratio of 4 : 3 means the width is 4x and the height is x, where x is some..."

It should say, "...the width is 4x and the height is 3x..."
tommywallach
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Re: Guide 3-page 39 problem set #1

by tommywallach Wed Jun 26, 2013 7:19 pm

Good catch, John!

I don't think that was Ghezas' problem on this one, but it's still a heck of a typo!

-t

P.S. Enjoying our class? : )