Answer :

This Shape is a Pentagon. Five sided figure.

There are 5 angles at a point. The sum of the 5 angles is 360.

Let each angle be x.

5*x = 360

x = 360/5

x = 72

The perpendicular divides the central angle 72 into 2 equal parts.

72/2 = 36

Angle 3 + 36 + 90 = 180        Sum of angles in Triangle

Angle 3 + 126 =  180

Angle 3 = 180 - 126

Angle 3 = 54 degrees.