Question

Can u prove that the sum of angle of a triangle is equal to 180⁰​

Answer 1

Step-by-step explanation:

Given :

A triangle ABC.

To prove :

∠A+∠B+∠C=180o⟹∠1+∠2+∠3=180o

Construction :

Through A, draw a line l parallel to BC.

Thus,

Therefore, ∠2+∠3=∠4+∠5

∠1+∠2+∠3=∠1+∠4+∠5  [adding∠1bothSide]

∠1+∠2+∠3=180o

Thus, the sum of three angles of a triangle is 180o

Answer 2

Step-by-step explanation:

draw a line parallel to BC and it has to go through A

and call that line as LM

so angle LAB = angle ABC( alternative angles)

same way angle MAC= angle ACB

so angle at A is straight angles

that means

angle LAB+angle BAC+angle CAM= 180

so

angle ABC+angle BAC+angle ACB=180

hence proved