Answer:
a) 150°
b) 30°
Step-by-step explanation:
It is easier to work the exterior angle first.
b)
The sum of exterior angles is 360°. The exterior angle at any vertex of a regular dodecagon will be 1/12 that:
360°/12 = 30° . . . the measure of one exterior angle
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a)
The measure of an interior angle will be the supplement of the adjacent exterior angle.
180° -30° = 150° . . . the measure of one interior angle
