Question

please don't give useless answer​

Answer 1

Step-by-step explanation:

1.In triangle DOC ,30°+30°+angle DOC=180°{sum of all the angles of the triangle}

therefore,angleDOC=180°-(30°+30°)=180°-60°=120°

2.Angle ADC=60°(given)

3.As angle ADC=angleBCD=60°(given)and angleDAB=100°(given)

therefore,angle ADC+angleBCD+angleDAB+angleABC=360°(sum of all the angles of the quadrilateral)

therefore,60°+60°+100°+angleABC=360°

now,angle ABC=360°-(60°+60°+100°)

angle ABC=360°-220°=140°

HOPE IT HELPS....