Answer:
m<ACD =
Step-by-step explanation:
From the question given, ΔACD is a right angled triangle. Then we can apply one of the properties of a triangle to it.
In the triangle ACD:
<ACD + <DAC + <ADC = 180 (sum of angles in a triangle)
<ACD + 40 + 90 = 180
<ACD + 130 = 180
<ACD = 180 - 130
<ACD =
With the application of the property of the sum of interior angles of a triangle, the measure of <ACD is .