In the diagram, line a is the perpendicular bisector of KM. What is the length of KM? 22 units 40 units 44 units 80 unit

We know that:

9 x - 5 = 7 x + 7 (because line a is tre perpendicular bisector of KM)

9 x - 7 x = 7 + 5

2 x = 12

x = 12 : 2

x = 6

Also: KM = 2 * (6 x + 4) = 2 * (6 * 6 + 4) =

= 2 * (36 + 4) = 2 * 40 = 80

Answer:

D) 80 units.