In a rhombus ABCD, if ACB =40°, then ADB =

The diagonals in a rhombus are perpendicular,

So,


BPC = 90o


From triangle BPC,


The sum of angles is 180°


So,


CBP = 180o – 40o – 90o


= 50°


Since, triangle ABC is isosceles


We have,


AB = BC


So,


ACB = CAB = 40o


Again from triangle APB,


PBA = 180o – 40o – 90o


= 50o


Again, triangle ADB is isosceles,


So,


ADB = DBA = 50o


ADB = 50o

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