If Mis the midpoint of segment AB find the coordinates of B

If Mis the midpoint of segment AB, find the coordinates of B; given that A = (-8.9) and M = (-6, 6). 18. Calculate the distance between A and B. 19. Find the equation in point-slope form of the line that is the perpendicular bisector of the segment between (16,-4) and (-2, -76). 20. In the box shown at the right, what is the length of the dashed line?

Solution

17 ) M = (-6 , 6) ; A = (-8, 9) .Let B be (x, y)

M= ((-8+x)/2 , (9+y)/2 )

So, -6 = (-8 +x)/2

x = -4

6 = (9+y)/2

y = 3

B( -4, 3)

18) Distance between two points = sqrt( (x2-x1)^2 +(y2-y1)^2 ) = sqrt( ( -4+8)^2 +(3-9)^2 )

= sqrt(16+ 36) = sqrt52

20) diagonal of a cuboid = sqrt(l^2 +b^2 +h^2)

                              = sqrt( 84^2 +5^2 +12^2) = 85 mm