Question

Prove that the opposite angles of an isosceles trapezium are supplementary.

Answer 1

SINCE , AB IS PARALLEL TO DC , TE ALTERNATIVE INTERIOR ANGLES ARE SUPPLEMENTARY
SO , THE ANGLES <A AND <B ARE SUPPLEMENTARY
THUS , <A AND <D =180..................................................................1
SIMILARLY , <B AND <D ARE SUPPLEMENTARY
<B +<C =180
<C =<D .
FROM 1 & 2,,
<A +C=180
THUS ,THE OPPOSTE ANGLES , (<A AND >B ) AND ( <B 7<D) ARE SUPPLEMENTARY