Go back
math thingy.... i'm not that smart

math thingy.... i'm not that smart

Posers and Puzzles

Clock
Vote Up
Vote Down

Find the area of a quadrilateral whose vertices have coordinates (-4, -6),

(-3, 5), (4, 7), and (5, -9).

Clock
Vote Up
Vote Down

why should I?

Clock
Vote Up
Vote Down

Originally posted by afx
why should I?
If you honestly need a reason then don't. I'm just looking for a little help on my math homework. Not that you could help me anyways :]

Clock
2 edits
Vote Up
Vote Down

Originally posted by RatskcorWagoner
If you honestly need a reason then don't. I'm just looking for a little help on my math homework. Not that you could help me anyways :]
are you looking for an analyitical answer?, because I did it graphically

here is what I get for the Area

77 + 49/2 + 11/2 + 192/18 + 225/32 + 77/96 = 125.5

like i said, probably not what your looking for?

Clock
Vote Up
Vote Down

Originally posted by joe shmo
are you looking for an analyitical answer?, because I did it graphically

here is what I get for the Area

77 + 49/2 + 11/2 + 192/18 + 225/32 + 77/96 = 125.5

like i said, probably not what your looking for?
I'm not really sure what i am looking for but I know that 125.5 is incorrect.
any other ideas?

Clock
1 edit
Vote Up
Vote Down

Originally posted by RatskcorWagoner
I'm not really sure what i am looking for but I know that 125.5 is incorrect.
any other ideas?
nope...can you point out the flaw in my method? In case your wondering what I did, I plotted the points, connected the lines, and divided the area into a rectangle and several triangles, summing the areas

What is the title of the Math course?

here is a link with some information:http://mathworld.wolfram.com/Quadrilateral.html

Clock
Vote Up
Vote Down

hmm well it is pre calc so i don't know it seems like the logical thing to do..

Clock
Vote Up
Vote Down

Originally posted by RatskcorWagoner
hmm well it is pre calc so i don't know it seems like the logical thing to do..
so, what is the area? Was I even close?

Clock
Vote Up
Vote Down

If I knew i wouldn't be asking anyone. haha
i will find out the answer tomorrow and will post it.
any other ideas?

Clock
Vote Up
Vote Down

Originally posted by RatskcorWagoner
If I knew i wouldn't be asking anyone. haha
i will find out the answer tomorrow and will post it.
any other ideas?
but how do you know it is not 125.5?

Clock
Vote Up
Vote Down

I broke it into 2 triangles.

One with sides of sqrt(122), sqrt(53), sqrt(233)...
One with sides of sqrt(257), sqrt(53), sqrt(260).

Using the formula A = 1/4 * sqrt( (A^2 + B^2 + C^2)^2 - 2*(A^4 + B^4 + C^4) ), I get the following..

Triangle 1
Area = 1/4 * Sqrt[(122 + 53 + 233)^2 - 2*(122^2 + 53^2 + 233^2)]
Area = 1/4 * Sqrt[408^2 - 2*(14,884 + 2,809 + 54,289)]
Area = 1/4 * Sqrt(166,464 - 2*71,982)
Area = 1/4 * Sqrt(22,500) = 150 / 4 = 37.5

Triangle 2
Area = 1/4 * Sqrt[(257 + 53 + 260)^2 - 2*(257^2 + 53^2 + 260^2)]
Area = 1/4 * Sqrt[570^2 - 2*(66,049 + 2,809 + 67,600)]
Area = 1/4 * Sqrt(324,900 - 2*136,458)
Area = 1/4 * Sqrt(51,984) = 228 / 4 = 57

Total Area = 37.5 + 57 = 94.5

Clock
Vote Up
Vote Down

Originally posted by geepamoogle
I broke it into 2 triangles.

One with sides of sqrt(122), sqrt(53), sqrt(233)...
One with sides of sqrt(257), sqrt(53), sqrt(260).

Using the formula A = 1/4 * sqrt( (A^2 + B^2 + C^2)^2 - 2*(A^4 + B^4 + C^4) ), I get the following..

Triangle 1
Area = 1/4 * Sqrt[(122 + 53 + 233)^2 - 2*(122^2 + 53^2 + 233^2)]
Area = 1/4 * Sqrt[408^2 - 2*(14,884 ...[text shortened]... (324,900 - 2*136,458)
Area = 1/4 * Sqrt(51,984) = 228 / 4 = 57

Total Area = 37.5 + 57 = 94.5
that looks to technical to be false, so you da person geepamoogle.

Clock
Vote Up
Vote Down

Pick's Theorem? Although I'll need a piece of graph paper for that.

Clock
Vote Up
Vote Down

so whats the answer?

Clock
Vote Up
Vote Down

Originally posted by joe shmo
are you looking for an analyitical answer?, because I did it graphically

here is what I get for the Area

77 + 49/2 + 11/2 + 192/18 + 225/32 + 77/96 = 125.5

like i said, probably not what your looking for?
Are we assuming the first # to be the X axis, and second # to be Y?
I got the 77, but I got 8+5.5+7+12+77 ,minus two small areas, which comes out to 109 and change.

Cookies help us deliver our Services. By using our Services or clicking I agree, you agree to our use of cookies. Learn More.