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xconfusedteenx
09-11-2005, 10:12 PM
ok, here's an example of a math problem i have.

In the drawing angle, CB bisects angle ACD, angle ACB=24x-4 and angle DCB=20x-4. Find the Missing values

x=_____ angle ACD=________ and angle ACB=_____

http://img345.imageshack.us/img345/253/mathdiagram4pk.png

for the answers my teacher had, x=1/2 angle ACD=16 and angle ACB=180*

I have absolutely no clue how he got he got 1/2 for x...could it possibly be wrong? but then again, i need to know how to set this problem up step by step.[/img]

09-11-2005, 10:20 PM

stapel
09-11-2005, 10:21 PM
I think there's a typo in the problem: You have m(ACB) = 24x - 4 and m(ACB) = 20x - 4. Are those both supposed to be the same angle? Or is one of them supposed to be something else?

Thank you.

Eliz.

xconfusedteenx
09-11-2005, 10:39 PM
ok, sorry, i didn't realize i had a typo in the problem, i fixed it :D

xconfusedteenx
09-11-2005, 10:45 PM
I'm adding in the drawing right now the diagram...

stapel
09-11-2005, 10:45 PM
If CB bisects the angle ACD, then m(ACB) = m(DCB). So set the two expressions equal, and solve for x. Then back-solve for the angle measures.

Eliz.

xconfusedteenx
09-11-2005, 10:47 PM
Well, thats the thing, i can't solve for x, when i put in the two numbers, am i suppose to add a 180 at the end? so will it be like

20x-4+24x-4=180

is that the way to set it up? cause ACB equals to 180

stapel
09-11-2005, 10:50 PM
Why are you adding the two angles, instead of setting them equal to each other? Why are you setting the angle-sum equal to 180°? Does the picture show that AD is a straight line?

Eliz.

xconfusedteenx
09-11-2005, 10:53 PM
well, in some problems that we have, if the angle is a supplementary angle it equals 180 degrees but when we set up certain problems we have to add 180 at the end, i'm confused

Well ACE is a straight line, and that equals 180, ack i'm so confused, i don't even know how to explain myself when it comes to this, dang sophmore geometry! lol

stapel
09-11-2005, 10:54 PM
Different exercises have different conditions and require different tools. There is nothing in this exercise that says that the two angles are supplementary. But there is something, as has been mentioned, that says that the angles are equal.

Set the angles' measures equal, and solve for x.

Eliz.

xconfusedteenx
09-11-2005, 10:56 PM
so how will I set the problem up to solve for x? 20x-4=24x-4

ack i don't know how to solve for x

gosh dang it! i know what it is! my teacher wrote the problem completely wrong! thats why i can't solve it! 1/2 is not the answer, its the answer for another number, like 1/2 of 16 is 8 or something, thats like a hint he's giving me....but i don't know how he got ACD to equal 16