The intersecting chords AB and CD are drawn in the circle. Find the value of the angle DAC, if the measure

The intersecting chords AB and CD are drawn in the circle. Find the value of the angle DAC, if the measure of the angle is ABC = 50 degrees, the measure of the angle is ACD = 40 degrees.

The inscribed angle ACD rests on the arc AD, then the degree measure of the arc AD = 2 * 40 = 80.

The inscribed angle ABC rests on the arc AC, then the degree measure of the arc AC = 2 * 50 = 100.

Then the arc CAD = AD + AC = 80 + 100 = 180.

The sought angle DАС is based on the СВD arc, the degree measure of which is equal to: СВD arc = 360 – СAD = 360 – 180 = 180.

Then the inscribed angle DАС = 180/2 – 90.

Answer: The DAC angle is 90.



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