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Skyrocket Away · Oct 4, 2008, 06:20 AM

I know I'm going to come off as dumb for asking for help, but I honestly can't figure them out. Can someone help me, please? I don't understand how to get the answer.. ):

galactus · Oct 4, 2008, 07:48 AM

For the first one, about the easiest way is to find the area of the white region and subtract from the total area of the rectangle.

Given the smaller shaded triangle, find the height of the rectangle by using Pythagoras.

$\sqrt{13^{2}-5^{2}}$

Then you have all the info to answer the question.

Skyrocket Away · Oct 4, 2008, 09:44 AM

Originally Posted by galactus

For the first one, about the easiest way is to find the area of the white region and subtract from the total area of the rectangle.

Given the smaller shaded triangle, find the height of the rectangle by using Pythagoras.

$\sqrt{13^{2}-5^{2}}$

Then you have all the info to answer the question.

That doesn't help at all!

starfirefly · Oct 4, 2008, 09:45 AM

These are very simple, but if you are looking for help glad to give it, but if you are looking for answers than don't bother

starfirefly · Oct 4, 2008, 09:48 AM

Hypotenuse - Wikipedia, the free encyclopedia

If you can figure out the third one, the first should be very easy

parttime · Oct 4, 2008, 02:48 PM

hey I'm not in this hunt, ust curious,
would the third one be:

Xsquared+xsquared= 16squared?

I've not had geometry in 40 years, this brought back bad memories. Lol

Britt198237 · Oct 5, 2008, 11:28 AM

Like the others have said... use the pythagorean theorum (sp?), use it to fine triangle ABE first. WHen you find the missing side length (side AE) it is equal in length to side CD... take the pythagorean theorum and find the area of triangle BCD.. add the two areas together and that will be the totally shaded area.. good luck

Britt198237 · Oct 5, 2008, 11:31 AM

Wait... just re-read the question.. you just need to use the theorum to find side lenth AE.. with that you will have your height and use the area formula for triangles (base*height)/2... you also use the length of AE for CD.. same formula.. add the sides.. wala

Unknown008 · Oct 5, 2008, 10:08 PM

Quicker that way for the first question. Do you know that the area of a triangle is basically half the area of a rectangle? You have the dimensions of the rectangle, as AB + BC (5+10 = 15), and by pythagoras', you have AE ( $\sqrt{13^2 - 5^2} = 12$

So, area of the triangle (both shaded and unshaded have the same area) is (0.5 x 12 x 15)= 90cm^2.

Unknown008 · Oct 5, 2008, 10:11 PM

Second, use Area = 0.5 x Base x Height to find the base.

48 = 0.5 x base WZ x 8
WZ = 12.

Then perimeter = sum of all sides.

Unknown008 · Oct 5, 2008, 10:14 PM

Third,

Originally Posted by parttime

hey I'm not in this hunt, ust curious,
would the third one be:

Xsquared+xsquared= 16squared?

I've not had geometry in 40 years, this brought back bad memories. lol

Yes, it's $x^2 +x^2 = 16^2$

Therefore

$2x^2 = 256$
$x^2 = 128$
$x = /sqrt{128}$

Skyrocket Away · Oct 6, 2008, 05:07 AM

Originally Posted by Unknown008

Third,

Yes, it's $x^2 +x^2 = 16^2$

Therefore

$2x^2 = 256$
$x^2 = 128$
$x = /sqrt{128}$

Thank you so much! Your answer was the only one that actually helped!

Can you help me with this one? I can't seem to figure it out.

Skyrocket Away · Oct 6, 2008, 05:10 AM

Originally Posted by Unknown008

Quicker that way for the first question. Do you know that the area of a triangle is basically half the area of a rectangle? You have the dimensions of the rectangle, as AB + BC (5+10 = 15), and by pythagoras', you have AE ( $\sqrt{13^2 - 5^2} = 12$

So, area of the triangle (both shaded and unshaded have the same area) is (0.5 x 12 x 15)= 90cm^2.

Okay, I understood everything, but the "90cm^2" part. What does "^2" mean? :confused:
Sorry, I'm dumb. /:

Skyrocket Away · Oct 6, 2008, 05:15 AM

Originally Posted by Unknown008

Second, use Area = 0.5 x Base x Height to find the base.

48 = 0.5 x base WZ x 8
WZ = 12.

Then perimeter = sum of all sides.

12 is the answer I got, but I'm not sure if that's the official answer. I understand what you put, but I don't understand if there is another step I have to take. Or if 12 is just the answer.

EuRa · Oct 6, 2008, 03:11 PM

With your last problem, you can simply put in values for each equation and solve. According to the balloon stats, the equation has to equal 44 when t = 3. So let's try 3.

1) h=60+16t (put in 3) h = 60 + 16 (3) = 60 + 48 = 108 (nope)

2) h=70+6t (put in 3) h = 70 + 6 (3) = 70 + 18 = 88 (NOPE)

3) h=80-4t (put in 3) h = 80 - 4(3) = 80 - 12 = 68 (Nope)

4) h=80-4t^2 (put in 3) h = 80 - 4(3^2) = 80 - 36 = 44 (YES)

5) h=90-14t^2 (put in 3) h = 90 - 14(3^2) = 90 - 126 = -36 (NO)

So only (4) works. That has to be the answer. To be sure, try using 2 and 4 for t... and I did. It works. It is the answer.

BTW, just by observing the answers, you can tell that the answers aren't (1) or (2). Those equations increase as your t value increases. You can also tell it can't be equation (3), because that's a constant decline, where-as the balloon isn't constantly declining. That narrows it down to (4) and (5), but (5) is declining way way way too fast. That should also be obvious. I could tell it was (4) before I even did a single Mathematical computation.

EuRa · Oct 6, 2008, 03:12 PM

Originally Posted by Skyrocket Away

Okay, I understood everything, but the "90cm^2" part. What does "^2" mean? :confused:
Sorry, I'm dumb. /:

^2 means squared.

So 4^2 means 4 squared, which equals 16.

k?

EuRa · Oct 6, 2008, 03:15 PM

Originally Posted by Skyrocket Away

12 is the answer I got, but I'm not sure if that's the official answer. I understand what you put, but I don't understand if there is another step I have to take. Or if 12 is just the answer.

The perimeter is the sum of all sides.

The bottom side is 12.

But then you got to add the other 2 sides.

12 + 10 + 10.

That's the official answer.

Unknown008 · Oct 7, 2008, 05:01 AM

I guess EuRa answered all your qyestions qhen I was not here. If you have anymore, don't hesitate to ask. Thanks.:)