Question

DELTA/Pg No.
I 1
Date
Prove
5180°
that sum of three angles of a fiangle​

Answer 1

The sum of all the angles in a ∆ is 180°

Answer 2

Answer:

How do we prove that the sum of the angles of a "five star" is 180 degrees?

An inscribed angle is half the measure of the arc it cuts off. A “five star” has five points so it cuts a circle into five arcs, the sum of these five arcs is 360 degrees so the sum of the five angles is 1/2 of 360 degrees or 180 degrees. Arc AB + Arc BC + Arc CD + Arc DE + Arc EA =360. But Arc AB = 2(Angle D), and Arc BC = 2(Angle E), and Arc CD = 2(angle A), and Arc DE = 2(Angle B), and Arc EA = 2(Angle C). So by substitution 360 = 2(A+B+C+D+E) then by dividing both sides of the equation by 2, (A+B+C+D+E) = 180.