Suppose point M lies on (line segment) CD, CM=2 x MD, and CD=18. What is the length of MD?
2006-08-17 12:54:41 · 15 answers · asked by athlete719 2 in Science & Mathematics ➔ Mathematics
Elana, I wasn't asking for the answer. I was asking what are the first steps to solving this problem. I've tried solving it for about 20 minutes and can't get the right answer.
2006-08-17 13:10:34 · update #1
I've drawn it out too, but thanks to the people who helped me out with the problem.
2006-08-17 13:14:47 · update #2
cm is twice as big as md
2x+x=18
3x=18
x=6
md=6
2006-08-17 13:00:03 · answer #1 · answered by good knower 3 · 0⤊ 0⤋
Let CM be X and MD be Y so:
CM=2MD becomes X=2Y
CD=18 is the whole line so the 2 parts of the line that you know are MD and CM or X and Y.
The equation you could make would be CM + MD= CD which becomes X+Y=18
you then have the 2 linear equations of:
X=2Y
X+Y=18
then you solve for the variables to get X=12, Y=6 and MD=Y=6
2006-08-17 13:12:00 · answer #2 · answered by Mustang2008 2 · 1⤊ 0⤋
First, subsitute the line segments for variables.
For example, let MD=x and since CM is twice as long, then CM=2x.
Now, CD= CM + MD= 18.
Since MD=x and CM=2x, then CM+MD=3x
CD=18, so 3x=18. Solving for x, you get x=6.
Subsitute 6 in for x in the original problem and you get:
MD=x=6 and CM=2x=2*6=12.
Thus, CM=12 and MD=6.
Hope that helps!
2006-08-17 13:04:04 · answer #3 · answered by knicksfan12 2 · 1⤊ 0⤋
Draw it out. I believe the answer is MD=6.
2006-08-17 13:02:05 · answer #4 · answered by jodaco01 2 · 0⤊ 0⤋
I would first draw a picture and label with the information that you have. You should be able to figure this out without using any hard techniques. You may want to try the guess and check method to get an idea of how the numbers relate.
2006-08-17 13:01:33 · answer #5 · answered by raz 5 · 0⤊ 0⤋
CD=18
CD=CM+MD
CD=2MD+MD (since CM=2MD)
18=3MD (since CD=18)
18/3=3MD/3 (dividing both sides by 3)
6=MD.
simple as that
2006-08-17 13:09:17 · answer #6 · answered by Anonymous · 0⤊ 0⤋
C-----------------M----------D
We're interested in the length of:
CM
MD
CD
Let's rename them just to make things easier for us:
CM is called X
MD is called Y
CD is called X + Y
Now, you can write two known equations:
(a) X = 2Y
(b) X + Y = 18
Replace the X value in equation (b) with 2Y from equation (a). You now have one equation:
2Y + Y = 18
You can easily solve for Y = 6. Then returning to equation (a) we find that X = 2 * 6 = 12.
Therefore, using the original naming convention:
CM = X = 12
MD = Y = 6
2006-08-17 13:09:22 · answer #7 · answered by tke999 3 · 0⤊ 0⤋
Look at this diagram
C--------------M--------D
|CD| = 18 ok?
We know that |CM| = 2 x |MD| (eq1); so the one is double the other
We also know that |CM|+|MD| = |CD| = 18 (eq2)
Substituting eq1 into eq2 gives
18 = |CM| + |MD| = 2 x |MD| + |MD| = 3 x |MD|
So |MD| = 6
2006-08-17 13:05:36 · answer #8 · answered by Anonymous · 0⤊ 0⤋
CM+MD=18
CM=2MD
substitute:
2MD+MD = 18
3MD = 18
MD = 6
screw the moral issues. i want my ten points.
2006-08-17 12:59:55 · answer #9 · answered by mathu9 2 · 1⤊ 2⤋
I am not doing your homework for you, frosh. Stick with it and work hard, and you will be fine. May God bless and keep you.
2006-08-17 13:00:37 · answer #10 · answered by blowry007 3 · 1⤊ 1⤋