Question

if abcd is an isosceles trapezium then prove that angle a = angle b

Answer 1

const a line parallel to ad from point c and extend an to f now afcd is a parallogram therefore FC =ad ad=bc so bc = FC in triangle bcf bc=cf so angle b = angle f. angle f +angle a =180 degree (Co interior) angle abc+anglecbf= 180 therefor by comparing we get angle a = angle b (angle cbf = cfb