An angle of a parallelogram is $20°$ less than its adjacent angle. Find the measure of all its angle.

In the figure, $ABCD$ is a parallelogram in which $\angle ADC=60°$ and $\angle ACB=70°$. Find the measures of $\angle DCB, \angle CAB$ and $\angle DAC$.

In the figure, $ABCD$ is a parallelogram. Find the values of $a, b, c$ and $d$.

In the figure, find the values of $a, b, c$ and $d$, given that $ABCD$ is a parallelogram.

In the figure, $ABCD$ is a parallelogram. $CE$ bisects $\angle C$ and $AF$ bisects $\angle A$. 

Is $\angle A=\angle C ?$  If the statement is true, give its reason.