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#3 Re: Help Me ! » i need help with this math problem » 2006-03-08 17:09:31

Or you could do it the mathmatical way:

3x + 2y = 34        (3 eyes for each martian, 2 for each human, is equal to 34)
x + y = 14            (martians and humans combine to 14 people total)

we need to solve for y, ill choose the second equation and get:
y=-x + 14

Now substitue that in for y in the first equation and simplify:
3x + 2(-x + 14) = 34
3x - 2x + 28 = 34
x = 6

Now since X stands for martians, we know we have 6 martians, leaving us with 8 humans.
If you plug those in for the first equation you will find 3(6) + 2(8) = 34, thus there are:

6 Martians (18 eyes) and 8 (16 eyes) Humans.

#5 Re: Help Me ! » Percentages » 2006-03-07 11:55:54

They both did it by going to 1% first, but you can also just turn 8% into a fraction.
Just put 8/100 (simplified as 2/25) and you will find out that fraction is equal to .08
Multiply .08 by 20 to get 1.6

Or you could simply move the decimal point... 8% is technically 8.0%, and if you want to convert that to a decimal, move the decimal point to spaces to the left, making it .08, and multiply that by 20 to get 1.6.

Other examples of moving the decimal point are 50% is equal to 50.0% move it 2 to the left and you get .5... .5 is equal to 1/2 and half of 20 is 10, so 50% of 20 would be 10.

#6 Introductions » Hello » 2006-03-07 11:35:21

Dionysus
Replies: 3

Hello everyone... im new to the forums. Im not going to be able to answer a lot of tough questions or anything as for I am only a sophmore in high school, and I'm just interested in learning some new problems, as well as some more types of math.
Thanks. big_smile

#7 Re: Help Me ! » Triangle » 2006-03-07 11:24:58

I'm assuming H is the height, making H perpendicular to BC.
Therefore triangle abh is a right triangle, so by using pythagorean theorem,

:
144-81=63
Square root that to get 3√7 for B
You can do the same thing for the triangle on the right. adding
:
9 + 81 = 90
Simplify root 90 to get 3√10 for D
This makes your total perimeter 12+3√10+3√7+3 = 15+3√10+3√7 or about 32.4241

To find the area just find the base B + C = 3√7 + 3 and multiply it by your height of 9, and dividing by 2. The answer comes out to be exactly:

+

or about 49.2176.

So to sum up, your appx area is 49.2176, and your apprx perimeter is 32.4241. If you need it exact, look above for the radicals. (All in feet)

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