1. Find the point of intersection of y-axis and the perpendicular bisector of line segment joining (3,6)and (-3,4)?

2. Determine the ratio in which (-6,a) divides the join of A(-3,-1) and B(-8,9). Also find the value of a.

3. The vertices of a triangle are (2,4),(5,k) and (3,10) and its area is 15 sq. units. Find the value of K?

sorry friend I am a bit busy to solve this for now but I can give you hints

Q1 The perependicular bisector will pass through the midpoint of two given points and will have slope such that it is perpendicular to the line joining points. use slope form and then put the point to eliminate variables.

Q2 Let (-6,a) divide it in Ratio of K:1 now apply section formula and solve.

Q3 Forumula for area of triangle with three vertices. Too lazy to write google it