Question

If angle ADB=70 degrees, what is the meas. of angle ABD=?
arc of AB=?
meas. of arc AD=?
Refer to picture below.

Answer 1

*Arc AB has measure 140* because the inscribed angle that cuts off the arc has measure 70 and an inscribed angle is half its arc.

Arc DAB is a semicircle so arc AD has measure 180 -140 = 40.

M<ABD = 1/2 (40) = 20