Question

answer this question​

Answer 1

$\huge {\bold {\red {s0lUtion...!}}}$

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Small angle = aADC

Large angle = aA'D'C'

aA + aB + aC + aADC = 360°

.... (¡)

[because, the sum angles of a quadrilateral is equal to 360°in quadrilateral ABCD]

aADC + aA'D'C' = 360°.... (¡¡)

[because, it forms a complete angle]

Eliminating (¡) and (¡¡), we get

aA + aB + aC + 360° - aADC =360°

aA + aB + aC = aADC

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$\huge {\bold {\red {Hope \: it \: helps}}}$