10.ABCD is a rhombus such that measure of angle ACB is 40º find the measure of angle ADC.

ADC = 100 degrees

Step-by-step explanation:

Please check attachment for diagrammatic representation of the Rhombus

From what we can see in the diagram;

angle CBD and CDB are equal

The reason for this is that we have an isosceles in triangle CBD

CBD = 90- ACB

CBD = 90-40 = 50

We need ADB to completely calculate ADC

CAB is also 40 from the isosceles ABC

That means DBA = 90 - CAB = 90-40 = 50

So from isosceles ABD, we have that ADB is also 50

Mathematically;

ADC = ADB + DBA

ADC = 50 + 50

ADC = 100