Question

prove that the sum of three angles of triangle is equals to 180​

Answer 1

${ \huge\fbox \pink {A}\fbox \blue {n} \fbox \purple {s} \fbox \green{w} \fbox \red {e} \fbox \orange {r}}$

To prove :

∠A+∠B+∠C=180°

⟹∠1+∠2+∠3=180°

Construction :

Through A, draw a line l parallel to BC.

Proof :

Since l∥BC.

Therefore,

∠2+∠3=∠4+∠5

∠1+∠2+∠3=∠1+∠4+∠5

∠1+∠2+∠3=180°

Thus, the sum of three angles of a triangle is 180°.