Question

in a Rhombus abcd if acb=40° then cad=​

Answer 1

ABCD is a rhombus and ACB = 40 deg. What is the value of <ADB?

Since <ACB = 40 deg, <BCD = 2*<ACB = 80 deg.

<ADC = 180-<BCD = 180–80 = 100 deg, so <ADB = 100/2 = 50 deg.

Another approach: Let AC and BD intersect at O.

There are 4 right angled triangles: In triangle OBC, <OCB = 40 deg, so <CBO = 90–40 = 50 deg which is the same as <ADB.