Can y’all plzzz help

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Step-by-step explanation:

m∠ADC = 20°

Step-by-step explanation:

A circle B has points B, C and D on the circumference.

m∠ABC = 40° [Cntral angle]

Since measure of the central angle is double of the inscribed angle by the arc

m∠ABC = 2(m∠ADC)

Here ∠ABC = Central angle

and ∠ADC = Inscribed angle

40° = 2(m∠ADC)

m∠ADC =

              = 20°

Therefore, measure of angle ADC is 20°.