Answer:
see explanation
Explanation:
note that ∠ APC = 90°
A
∠ BPC + ∠ APB = ∠ APC , that is
∠ BPC + 50° = 90° ( subtract 50° from both sides )
∠ BPC = 40°
B
• the measure of an arc is the same as the degree measure of the central angle that intercepts it
∠ APB = 50° ← central angle , then
m AB = 50°
similarly m BC = 40°
C
the sum of the measures of the arcs in a circle is 360° , then
m ADC = 360° - m AC = 360° - 90° = 270°
D
m ADB = m ADC + m CB = 270° + 40° = 310°