Question

Find the indicated arc and angle measures:

с
D
F
DO
B
70960
E
A
arc AB Degree:
arc BC Degrees:
arc ABC Degrees:
arc CDB Degrees:

Answer 1

arc AB = 70°

arc BC = 110°

arc ABC = 180°

arc CDB = 250°

Explanation:

Since these angles are not inscribed, but are at the center point of the circle, the angles and arcs will be the same measure.

Solve for arc AB:

Angle AFB = 70°, so arc AB = 70°

Solve for arc BC:

Angle AFC is a straight angle so it is 180°. To find angle BFC, subtract angle AFB from 180°.

180 - 70 = 110°

Since angle BFC = 110°, arc BC = 110°

Solve for arc ABC:

Add arc AB and arc BC together.

70° + 110° = 180°

arc ABC = 180°

Solve for arc CDB:

There are 360° in a cirlce. To find arc CDB, subtract arc BC from 360°.

360° - 110° = 250°

arc CDB = 250°