Mid point (8,2) endpoint (8,3)

Question

Can someone find the other endpoint?

Answer 1

If you sketch this, it is clear that the other endpoint is (8,1). A way to solve this:

If we label the endpoints A and B and the midpoint M

M = (A+B)/2 = A/2 + B/2

Then, if we know M and B,

M = A/2 + B/2

A/2 = M - B/2

A = 2M - B

A = 2(8,2) - (8,3)

A = (16-8,4-3)

A = (8, 1)