Midpoint of the line segment

Highcharts Example
Definition:The point of a line segment or curvilinear arc that divides it into two parts of the same length.
The Midpoint M of the line segment joining the points (x1, y1) and (x 2, y 2) is

Example :
Calculate the Midpoint of the line segment joining the points (3,4) and (5,6) is,

X1 = , Y1 =
X2 = , Y2 =
 
Midpoint =