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If the measure of angle PLA is 110 then the measure of angle PDA is 220. An inscribed angle (that touches the inside surface of the circumference) has a measure half as large if the angle's middle point (in this case D) is at the center of the circle. The measure of angle PDA will be the same as the measure of arc length as PYA which the angle would encompass. Thus, 220=12x-20
Add 20 to both sides of the equation.
240=12x Divide both sides by 12
The answer is C.
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