Question

AC is a diameter, points B and D are on the circle, the measure of arc AB=60º, and m∠ACD=40º. Find m∠DAC

Answer 1

Angle ADC is 90 degrees by definition since D is on the circle and AC is the diameter. So, in triangle ADC, you got one angle that is 90 degrees. The second angle ACD is given as 40 degrees. What is the 3rd angle in that triangle?

Answer 2

I dont know

Answer 3

Well....three angles of a triangle have to add up to 180 degrees. That should help.