4) Prove that the sum of measure of all angles in a triangle is 180°. fast plzzzzz​

Question

4) Prove that the sum of measure of all angles in a triangle is 180°.
fast plzzzzz​

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Natalia 3 weeks 2021-09-04T01:26:00+00:00 2 Answers 0 views 0

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    0
    2021-09-04T01:27:12+00:00

    Given :

    A triangle ABC.

    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=∠4 …….eq(i)

    And, ∠3=∠5……eq(ii)

    adding eq(i)and(ii)

    Therefore, ∠2+∠3=∠4+∠5

    ∠1+∠2+∠3=∠1+∠4+∠5 [adding∠1bothSide]

    ∠1+∠2+∠3=180 °

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

    0
    2021-09-04T01:27:33+00:00

    Answer:

    all sides of a triangle are equal so angle formed between them will also be equal

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