Respuesta :

calculista
prove
 m∠5+m∠2+m∠6=180°

we have that
m∠1+m∠2+m∠3=180°   equation I

m∠1=m∠5  -------- > internal alternate angles  equation 2

and

m∠6=m∠3-------- > internal alternate angles    equation 3

I substitute  equation 2 and equation 3 in equation I

m∠1+m∠2+m∠3=180°-------- > m∠5+m∠2+m∠6=180°------- > is ok

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