Question

prove that the sum of a quadrilateral is 360°​

Answer 1

Answer:

THE FORMULA FOR FINDING MEASURE OF ANGLE=(n-4)90° where n is no. of sides

so angle of quad=(4-4)90

=90°

so since one angle is 90° so 4 angles =4×90

=360° hence proved

Answer 2

PROOF :-

In a Quadrilateral,

The sum of two adjacent angles is equal to 180°

Hence,

$\angle {BAC} +\angle$ ACD = 180° __________________ ( i )

$\angle {ABD} +\angle$ BDC = 180° _____________________ ( ii )

On adding ( i ) and ( ii )

( $\angle {BAC} + \angle {ACD}) +( \angle {ABD} + \angle {BDC}$ )

= 180° + 180°

= 360°

Hence, Proved ✔

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$\huge\mathbb\red {BE\:BRAINLY:)}$