Two angles are supplementary with measures m-angle ACB = 4x° and m-angle BCD = (6x + 50)°, what is the measure of angle ACB?

Since the angles are supplementary, their measures add up to 180°.

So, we can set up an equation:
m-angle ACB + m-angle BCD = 180°
4x + 6x + 50 = 180

Combine like terms:
10x + 50 = 180

Subtract 50 from both sides:
10x = 130

Divide by 10:
x = 13

Now, substitute x back into the measure of angle ACB:
m-angle ACB = 4x
m-angle ACB = 4(13)
m-angle ACB = 52°

So, the measure of angle ACB is 52°.