end point: find end point given midpoint, other endpoint  TOPIC_SOLVED

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end point: find end point given midpoint, other endpoint

Postby foxr1der31 on Tue Jul 07, 2009 2:43 am

Find the coordinates of the other endpoint when you are given the midpoint and one of the endpoints.

endpoint1 = (3,5) and midpoint = (-2,0) help and tell me how to do it

here is the formula but i dont know what do make of it maybe u guys can

x = (x2 + x1)

-2 = (1 + x1) (Distributive Property)

x1= - (subtract from both sides)

x1= -5 (multiply both sides by 2)

We now know that the x-coordinate of the missing endpoint is -5.

We will now solve for the missing y-coordinate in the same manner.

y = (y2 + y1)

4 = (2 + y1)

4 = 1 + y1 (Distributive Property)

y1 = 3 (Subtract 1 from both sides)

y1 = 6 (Multiply both sides by 2)

We have now found the coordinates of the missing endpoint:

(-5,6)
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  TOPIC_SOLVED

Postby stapel_eliz on Tue Jul 07, 2009 1:41 pm

You can check your solution by plugging it and the original point into the Midpoint Formula and making sure you end up with the correct midpoint value:

. . . . .

Since this does not match the given midpoint, then your solution is unlikely to be correct.

Let's try working directly from the Formula:

. . . . .

Multiplying through by 2, we get:

. . . . .

Then x - 3 = -4 and y - 5 = 0. Where does this lead...? :wink:
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