Answer:
Explanation:
a) the opposite angles of a quadrilateral inscribed in a circle are supplementary
70 + angle D = 180
angle D = 180 - 70
angle D = 110 degrees
b) DAB is a semicircle, so angle A and angle C are two circumference angles whose sides passes through the extremes of the diameter.
The centre angle of a semicircle is 180 degrees and its circumference angle is half that measure, so its value is 90 degrees
A = 90 degrees
C = 90 degrees