Question

In the Fig., ABCD is a parallelogram in which: LDAB= 80° and LDBC=60°. Find LCDB and LADB.

Answer 1

ADB=DBC(Alternate interior angles)
ADB=60°
In triangle BCD
AngleBCD=DAB (opposite angles of parallelogram are equal)
angleBCD=80°
angleCDB+BCD+DBC=180°(angle sum property of triangle
CDB+80°+60°=180°
CDB=180°-140°
CDB=40°