Question

find the addition of all the outer angles of a star

Answer 1

A star comprises of two triangles with the angles of the triangle forming the outer angles of a star.
                   We know that the sum of angles of a triangle is 180 degrees so the outer angles of a star = 2 x 180 degrees
                                = 360 degrees 
Hope that helps!!
 

Answer 2

In the center is a 5-sided regular polygon (a regular pentagon). The sum of the interior angles of a polygon is gotten by the formula:
SUM OF INTERIOR ANGLES = (NUMBER OF SIDES - 2) * 180°
 For a 5-sided polygon (pentagon) this is (5-2)*180° = 3*180°=540°
Since all 5 angles of a regular pentagon are equal, each interior angle of the regular pentagon is 540/5=108

Its suppplement is found by subtracting 180°-108°=72°. We'll mark it 72°:

That 72° angle is one of the base angles of an isosceles triangle. So we'll mark the other base angle 72° also.

Now we can find the angle at the top point of the star by adding the two equal base angles and subtracting from 180°. 72° + 72° = 144° 180° - 144° = 36° So each point of the star is 36°