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in the circl below, AD is diameter and AB is tangent at A. Suppose mADC=228*, find the measures of mCAB and mCAD. Type your numerical answers without units in each blank.

in the circl below, AD is diameter and AB is tangent at A. Suppose mADC=228*, find-example-1

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Given:

AD is diameter of the circle, AB is the tangent, and measure of arc ADC is 228 degrees.

To find:

The
m\angle CAB and
m\angle CAD.

Solution:

AD is diameter of the circle. So, the measure of arc AD is 180 degrees.


m(arcADC)=m(arcAD)+m(arcDC)


228^\circ=180^\circ+m(arcDC)


228^\circ-180^\circ+=m(arcDC)


48^\circ+=m(arcDC)

The measure inscribed angle is half of the corresponding subtended arc.


m\angle CAD=(1)/(2)* m(arcDC)


m\angle CAD=(1)/(2)* 48^\circ


m\angle CAD=24^\circ

AB is the tangent. So,
m\angle BAD=90^\circ because radius is perpendicular on the tangent and the point of tangency.


m\angle BAD=m\angle CAB+m\angle CAD


90^\circ=m\angle CAB+24^\circ


90^\circ -24^\circ=m\angle CAB


66^\circ=m\angle CAB

Therefore,
m\angle CAB=66^\circ and
m\angle CAD=24^\circ.

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