Points A, B, C, D lie in this order on the circumference of a circle. Minor arc AC is 160°, and minor arc BD is 150°. If B bisects minor arc AC, then what is the measure of minor arc AD?
Choose the correct option:  A) 80°  B) 130°  C) 140°  D) 160°  E) 220°
B bisects minor arc AC means Arc BC is 80 degrees. Now , we have arc BD = 150, therefore CD = 70.   Now, Arc AC = 160 , CD = 70 =&gt; Arc AD = 360-230= 
<gadget id="calculator">360-230</gadget>
<output>130</output>
130   Answer 130°
<result>B</result>
Points A, B, C, D lie in this order on the circumference of a circle. Minor arc AC is 160°, and minor arc BD is 150°. If B bisects minor arc AC, then what is the measure of minor arc AD?