*see attachement for the diagram that is being referred to
Answer:
m<ACB = 50°
Step-by-step explanation:
From the diagram, <DCB is a right angle = 90°
Therefore:
m<DCA + m<ACB = 90° (complementary angles)
m<DCA = 40° (given)
Thus:
40° + m<ACB = 90° (Substitution)
m<ACB = 90° - 40° (Subtraction property of equality)
m<ACB = 50°