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# My 13 year olds math homework.. LOL we both dont get it.. Can you explain?

Here is the question...

The Point on segment AB that is equidistant from A and B is called the midpoint of AB. For each of the following find coordinates for the midpoint of AB
(a) A=(-1,5) and B=(5,7) (b)A=(m,n) and B=(K,L)

She is supposed to graph it.. heck I dont even understand the question lol

Asked by Anonymous at 11:06 PM on Sep. 1, 2009 in Teens (13-17)

• FIX!

(a) A=(-1,5) and B=(5,-7)

Sorry the 7 is a negative

Answer by Anonymous at 11:08 PM on Sep. 1, 2009

• OMGosh .. Good Luck with that. I'm horrible in math and that sounds like another language to me. LOL

Answer by NOLAmommaKRYS at 11:08 PM on Sep. 1, 2009

• Wow! At 13 I wasnt doing math like that! Good luck.

Answer by MommyLee08 at 11:10 PM on Sep. 1, 2009

• She needs to graph it first. A= X and B = Y
plot the numbers for A on the X axis and B on the Y axis.

Answer by legalmommy101 at 11:12 PM on Sep. 1, 2009

• (2, -3) for the first answer
why doesnt she know this?

Answer by Anonymous at 11:20 PM on Sep. 1, 2009

• If you plot this on a graph, you'll see a line going from the upper left quadrant to the lower right quadrant. Think of this as the hypotenuse of a right triangle. Draw a straight line from (-1,5) to (5,5) and you see that length is 6. Draw a straight line from (5,-7) to (5,5), and this has a distance of 12. So your sides are 6 and 12.

Use the Pythagorean theorem of 6^2 + 12^12 = x^2 = 36+144 = 180 = (3*3*2*2*5). x = 6* sqrt(5).

Half this distance is 3*sqrt(5)

Answer by anng.atlanta at 11:24 PM on Sep. 1, 2009

• Oops, that's 6^2 + 12^2 = 36 + 144

Answer by anng.atlanta at 11:25 PM on Sep. 1, 2009

• She doesnt know this because her teacher got them Algebra books instead of Geometry books and by the time he realized his mistake it was to late to get the kids the proper books. She has nothing to go off. No examples or anything Just a piece of printed paper with the questions

Answer by Anonymous at 11:32 PM on Sep. 1, 2009

• Here's another way to solve it algebraically. Also uses the Pythagorean theorem.

http://www.tpub.com/math2/2.htm

Answer by anng.atlanta at 11:36 PM on Sep. 1, 2009

• Start with the second part: finding the midpoint of: A=(m,n) and B=(K,L)

The 'x' part of the mid point can be found by calculating the distance between the 'x' of A and of B
The distance is K - m
So the "x' value of the midpoint would be (K-m)/2

For the 'y' part of the midpoint, calculate the distrance between the y values: L-n
So the "y" value of the midpoint would be (L-n)/2

The midpoint, therefore, is ((K-m)/2),(L-n)/2)

For the first part of the question, use the above logic, but replace the values with the other coordinates for A=(-1,5) and B=(5,-7)

For the x value, you take (5 - (-1))/2 so the value is 6/2, thus 3
For the y value, you take (-7-5)/2 so the value is -12/2, thus -6

The midpoint of A=(-1,5) and B=(5,-7) is (3,-6)

Answer by PhillyinFrance at 4:42 AM on Sep. 2, 2009

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