Question

Prove That sum of measure of all angles in triangles is 180°​

Answer 1

Answer:

Step-by-step explanation:

Given : ABC is a triangle

RTP :   ∠ABC  + ∠CAB + ∠ACB = 180°

Construction ;  draw  EF ║ BC  through A

Proof :

∠ABC = ∠ EAB (ALTERNATE  ANGLES)

∠BCA = ∠FAC (ALTERNATE ANGLES)

∠EAB + ∠BAC  + ∠FAC = 180° (SUM OF ALL LINEAR ANGLES AT A )

SUBSTITUTE :  ∠EAB = ∠ABC  AND  ∠FAC =  ∠BCA

SO ,

∠ABC  + ∠CAB + ∠ACB = 180°

HENCE , PROVED

Answer 2

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• Sum of measures of all angles of a triangle is 180°.

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More To Know :-

• A triangle is a polygon with three edges and three vertices.

• A triangle with vertices A, B and C is denoted as ∆ABC.

• Sum of all angles of a triangle is always 180°.

• The measure of an exterior angle is sum of it's two interior angles that are not adjacent to it.

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