On the Cartesian plane, the midpoint between two points A(a,b) and B(c,d) is M(m,n) . If A is moved vertically upwards 20 units and horizontally to the right 14 units, and B is moved vertically downwards 4 units and horizontally to the left 2 units, then the new midpoint between A and B is \(M'\). What is the distance between \(M\) and \(M'\) ?
Let M = [ ( a + c) / 2 , (b + d) / 2 ] = (m, n)
A' = (a +14 , b + 20) B' = (c - 2, d - 4)
So M' = [ ( [a + c] + 12) / 2 , ( [b + d] + 16)/ 2 ] = ( m + 6, n + 8)
So..... the distance between M and M' is
√ [ (m + 6 - m)^2 + ( n + 8 - n)^2 ] = √ [ 6^2 + 8^2] = √ [36 + 64] = √100 =
10 units