Click to see a step-by-step slideshow. STEP 2: Label the angle you know and colour in the angle arc. Colour in the opposite angle in the same colour, and the other two angles in a different colour.

The second shape is not a cyclic quadrilateral. One corner does not touch the circumference. The opposite angles in a cyclic quadrilateral add up to 180°.

case 1<BR>In 2D coordinate system the sum of the angles of all quadrants=360 degree= 2pi radian<BR>in (x,y) plane<BR>Case 2<BR>In 3D coordinate system (x,y,z) I took 3 possible ...