Geometry Question

[BoldAsLove]

We are having a bunch of review in trig, and I forgot how to do this...ive tried the pythagorean theorem but it doesent quite work...anybody know?

Right triangle with hypotenuse 4x + 20, a leg 20, and a leg 3x....find x

 

[BoldAsLove]

anyone know?

 

[fatty4ksu]

whata kinda right triangle?

 

[BoldAsLove]

it doesent say

 

[FleshLight]

16x^2+40x+400=400+9x^2
7x^2+40x=0

Plug into quadratic

 

[bonkers325]

20^2 + 9(x^2) = (4x+20)^2

solve for x

 

[hypn0tik]

Originally posted by: BoldAsLove
We are having a bunch of review in trig, and I forgot how to do this...ive tried the pythagorean theorem but it doesent quite work...anybody know?

Right triangle with hypotenuse 4x + 20, a leg 20, and a leg 3x....find x

Try again.

 

[BoldAsLove]

when i do the PT i just get 3x^2=4x^2

 

[hypn0tik]

Originally posted by: BoldAsLove
when i do the PT i just get 3x^2=4x^2

Do you know how to square a binomial?

 

[fatty4ksu]

Originally posted by: hypn0tik

Originally posted by: BoldAsLove
when i do the PT i just get 3x^2=4x^2

Feel free to PM me for math and EE help.

LOL

 

[BoldAsLove]

Originally posted by: hypn0tik

Originally posted by: BoldAsLove
when i do the PT i just get 3x^2=4x^2

Do you know how to square a binomial?

yes

 

[PurdueRy]

Originally posted by: fatty4ksu

Originally posted by: hypn0tik

Originally posted by: BoldAsLove
when i do the PT i just get 3x^2=4x^2

Feel free to PM me for math and EE help.

LOL

What's so funny...

Also...what does it even matter what "type" of right triangle it is....

 

[BoldAsLove]

it could be an isoscoles right trange but its not

 

[bonkers325]

Originally posted by: BoldAsLove
when i do the PT i just get 3x^2=4x^2

you cant do basic trig if u cant get the basic arithmetic right

do you know how to multiply binomials?

 

[cheezmunky]

this isn't a right triangle and it isn't solvable without an angle

 

[Cooler]

Rermber FOIL!

 

[fatty4ksu]

0

 

[ForumMaster]

use FOIL = First Out In Last
i learned it in 6th grade if i recall. for example, if i have (3x-5)(5x+7)=0, first i do the 3 time 5 and get 15x^2, then i multiply the 3x time the 7 and get 21x, then the -5 time the 5x and get -25x, then -5 time 7 which is -35. all in all, it turns out like this: 15x^2-4x-35 = 0 try that out on the prob and you'll get it. i got it using this trick, but if i tell u the answer, u won't leaarn anything, will u? try again and good luck!

edit:srry. didn't see that u already said u knew how. alright then, do u have anyangle besides the 90 degree angle which u might be able to do sin,cos, or tan on?

 

[ArJuN]

a^2 + b^2 = c^2
a = 3x
b = 20
c = 4x + 20
(3x)^2 + (20)^2 = (4x+20)^2
9X^2 + 400 = 16X^2 + 80x + 80x + 400
9X^2 + 400 = 16X^2 + 160x + 400
0 = 7x^2 + 160x
0 = x(7x + 160)
...wait a minute...lol
yea..my geometry skills don't seem to be upto par..

 

[chuckywang]

Did it in my head. x=160/7

 

[bonkers325]

Originally posted by: ArJuN
a^2 + b^2 = c^2
a = 3x
b = 20
c = 4x + 20
(3x)^2 + (20)^2 = (4x+20)^2
9X^2 + 400 = 16X^2 + 80x + 80x + 400
9X^2 + 400 = 16X^2 + 160x + 400
0 = 7x^2 + 160x
0 = x(7x + 160)
...wait a minute...lol
yea..my geometry skills don't seem to be upto par..

the issue is the problem - i believe he has some numbersm ixed up

 

[PurdueRy]

Originally posted by: chuckywang
Did it in my head. x=160/7

fixed

 

[fatty4ksu]

Originally posted by: chuckywang
Did it in my head. x=160/9

EMAW

 

[BoldAsLove]

Originally posted by: BoldAsLove
We are having a bunch of review in trig, and I forgot how to do this...ive tried the pythagorean theorem but it doesent quite work...anybody know?

Right triangle with hypotenuse 4x + 1, a leg 20, and a leg 3x....find x

 

[JujuFish]

Originally posted by: PurdueRy

Originally posted by: chuckywang
Did it in my head. x=-160/7

fixed

Fixed.