Could anyone be so kind as to help me with my math homework?

[LOVEDISNEYLAND]

I am having a real tough time figuring this out. This is for Math 101 (Prealgebra) this is one of the last classes I need to graduate and I'm so bad at math. I can't even begin to explain how bad. Could someone please help me?

Here is the question:

Recently, Fry's Electronics advertised a TV that had an aspect ratio of 16:9. The TV was also described as having a 36 inch screen. Use ratio, proportion, and the Pythagorean Theorem to find the length and width of the actual screen. Round final answer to three decimal places.

I have already studied the Pythagorean Theorem but, am still confused on how to do this project and present it on paper as a business presentation. Would anyone be so nice, as to help me with this? Thank You!

 

[monkey68]

I don't have a calculator handy, but this is how I would approach it. 36 inch screen means the diagonal is 36 inches, so according to PT, you should have

a^2 + b^2 = 36^2

If the aspect ratio is 16:9, then 16x should be the length, and 9x should be the width, or whichever way it goes, so then

(16x)^2 + (9x)^2 = 36^2

Then you can solve for x, and multiply it by the original aspect ratio. So lets say x comes out to be 1.5, you would multiply both 16 and 9 by 1.5 to get the dimensions.

Not sure if that's exactly right, but that's what first came to my mind.

 

[jlima]

I am having a real tough time figuring this out. This is for Math 101 (Prealgebra) this is one of the last classes I need to graduate and I'm so bad at math. I can't even begin to explain how bad. Could someone please help me?

Here is the question:

Recently, Fry's Electronics advertised a TV that had an aspect ratio of 16:9. The TV was also described as having a 36 inch screen. Use ratio, proportion, and the Pythagorean Theorem to find the length and width of the actual screen. Round final answer to three decimal places.

I have already studied the Pythagorean Theorem but, am still confused on how to do this project and present it on paper as a business presentation. Would anyone be so nice, as to help me with this? Thank You!

TVs are normally measured on the diagonal. So, the "c squared" part of the imaginary triangle is 36 inches. The "a squared" part is the height. the b squared part is the width.

See here for a definition of aspect ratio:

http://en.wikipedia.org/wiki/Aspect_ratio_(image)

or, width divided by height

So, b squared divided by a squared is 36, for the TV in the math problem.

Does that help.

 

[LOVEDISNEYLAND]

I don't have a calculator handy, but this is how I would approach it. 36 inch screen means the diagonal is 36 inches, so according to PT, you should have

a^2 + b^2 = 36^2

If the aspect ratio is 16:9, then 16x should be the length, and 9x should be the width, or whichever way it goes, so then

(16x)^2 + (9x)^2 = 36^2

Then you can solve for x, and multiply it by the original aspect ratio. So lets say x comes out to be 1.5, you would multiply both 16 and 9 by 1.5 to get the dimensions.

Not sure if that's exactly right, but that's what first came to my mind.

I'm sorry but I'm going to ask a stupid question so here goes, I can't remember what ^ sign means? I told you I was bad at math. It's starting to make sense. Thank you!

 

[meliss8599]

This website is fantastic for any math problems you may have. It helped me out quite a bit in college. Check it out and see if it helps.

http://mathforum.org/dr.math/

 

[monkey68]

I'm sorry but I'm going to ask a stupid question so here goes, I can't remember what ^ sign means? I told you I was bad at math. It's starting to make sense. Thank you!

It means to square it. I don't know if it's possible to do a superscript on here, so that symbol is used on calculators when you're raising something to whatever power, in this case, raising the number to the power of 2.

Also, when you get to this step:
(16x)^2 + (9x)^2 = 36^2

Don't forget that you have to square the number as well as the x, and then you will have to factor out the x to solve it.

 

[DisneyWalker44]

The problem isn't clear unless you know something about TVs. Basically, the problem is you have a rectangle. The ratio of the long side to the short side is 16:9. And the diagonal is 36 inches. How long are the long side and the short side?

We know that the long side and short side have a ratio of 16:9. So we can say the long side is 16x and 9x.

We also know - from the Pythagorean theorem - that the sum of the square of the sides equals the square of the hypotenuse.

Putting those two facts together, we come up with 16x squared + 9x squared = 36 squared. We normally write squared by putting an superscript "2" after the number. But since it's hard to type that, people just write ^2.

So we have (16x)^2 + 9x^2 = 36^2.

Working through the math, we have 256 x^2 + 81 x^2 = 1296

337 x^2 = 1296

x^2 = 3.84569...

x = 1.961

Since the long side was 16x, and the short side was 9x, the length and width were...

31.3777 and 17.649

Doing a quick check

31.377 squared = 984.516
17.649 squared = 311.487
36 squared = 1296

984.516 + 311.487 = 1296.003 (close enough due to rounding)

Hope this helps....

 

[LOVEDISNEYLAND]

ahhhhhh! When I square 16, I get 256 and when I square 9, I get 81. What am I doing wrong? It's not equal to 36. I'm so confused

 

[laurie31]

ahhhhhh! When I square 16, I get 256 and when I square 9, I get 81. What am I doing wrong? It's not equal to 36. I'm so confused

Disneywalker's post explains it very well

You have started right, but now you need to continue.
256x squared + 81x squared = 36 squared, which is 1296.

And...believe it or not, you will use stuff like this in Real Life. We just had to figure out how much flooring to buy for a room that's L-shaped.

 

[PollyannaMom]

ahhhhhh! When I square 16, I get 256 and when I square 9, I get 81. What am I doing wrong? It's not equal to 36. I'm so confused

You did both of those right; you just forgot to square the 36, too! DisneyWalker44's post has it there.

 

[donald&daisy]

I can offer no help. I just want to say that I'm really impressed with people who can do this stuff. I made it through four years of college (graduated cum laude) and just finished law school and I couldn't help you with this even if my life depended on it (well, maybe if it really depended on it, but it has been a looooong time).

 

[doconeill]

ahhhhhh! When I square 16, I get 256 and when I square 9, I get 81. What am I doing wrong? It's not equal to 36. I'm so confused

It wasn't 16 squared and 9 squared, it is 16 times X, which is then squared, plus 9 times X, squared, equals 36 squared.

The problem itself is to figure out what X is, which DisneyWalker44 shows.

There are various notations for showing these with limited text input, and that makes it hard to show you.

Saying "X squared" can be written X^2, or X**2, as two examples. Of course, if you aren't used to those syntaxes, it will just confuse you more.

 

[LOVEDISNEYLAND]

YEA!!! FOR ME!!! IT FINALLY CLICKED!!! After looking at the problem and with all your guys help and using a couple of four letter words because my brain was fighting myself, I finally got it!!! THANK YOU GUYS FOR ALL YOUR HELP!