In parallelogram abcd, m∠a = 24°. what are the measures of angles b, c, and d? justify.

The sum of the angles in a parallelogram is 360°. 

a+b+c+d=360°

The opposite angles in the parallelogram are congruent.

a=c

b=d

So if a=24°... and we know a=c, then c=24°.

a=24

c=24

b=?

d=?

a+b+c+d=360°
plug in the data we know
24+b+24+d=360
48+b+d=360
b+d=312

If b+d=312, and we know that they are congruent, then to find their values just divide 312 by 2

312/2=156°

b=156°

d=156°

The answer is the last sentence dude, mm=84°.