Question

prove that sum of 3 angles of triangle is 180​

Answer 1

Answer:

So, the angle sum ∠A + ∠B + ∠C is equal to the angle sum ∠A' + ∠B' + ∠C'. The three angles A', B', and C' form together a straight angle (they are along the line l). So, their angle sum is 180°.

Answer 2

let the three angles of a triangle be x

× + × + × =180

3×=180

×=180÷3

×=60

all the three angles of a triangle is 60

60 + 60 + 60 =180

Hence, proved