+9519 "The interior acute angles are congruent" tells you it is a regular pentagram, so the measure of interior acute angle = 180/5 = 36 degrees. (I divided by 5 because it is a pentagram(5-gram) .)
Now you draw a straight line like this:
Calculate the angles in the triangle formed:
the base angles of the isosceles triangle is 72 degrees.
As the line drawn is a straight line, so the exterior angle is 108 degrees.
Measure of internal reflex angle = 72 * 2 + 108 degrees = 252 degrees
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