Question

ABCD is a rhombus such that ∟ADB = 50°, then what is the measure of ∟ACB?

Answer 1

Here it is 130
As By supposing AB and CD as transversal we know that sum of a pair of its side=180
Hence,50+angle ACB=180
So, angle ACB=130 degree

Answer 2

opposite angles of rhombus are congurent.
angleD=angleB
angleB=50measure of all angles of rhombus is 360
A+B+C+D=360
A+50+C+50=360
A+C+100=360
A+C=360-100
A+C=260

But A=C
A=C=260÷2
A=C=130

angleACB=130