Answer:
The measure of arc BC is 130° ⇒ 1st answer
Step-by-step explanation:
In a circle:
- The measure of an arc is equal to the measure of the central angle subtended by it
- The measure of an arc is equal to double the measure of the inscribed angle subtended by it
- Central angles subtended by the same arc are equal in measures
- Inscribed angles subtended by the same arc are equal in measures
- The measure of central angle is double the measure of the inscribed angle which subtended by its arc
∵ Angle BDC is an inscribed angle
∵ It is subtended by the arc BC
- By using the 2nd fact above
∴ The measure of arc BC = 2 × the measure of ∠BDC
∵ The measure of angle BDC is 65 degree
∴ The measure of arc BC = 2 × 65°
∴ The measure of arc BC = 130°
The measure of arc BC is 130°
