Math Is Fun Forum

  Discussion about math, puzzles, games and fun.   Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ • π ƒ -¹ ² ³ °

You are not logged in.

#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)

Board footer

Powered by FluxBB