Question

a quadrilateral abcd is inscribed such that ab is daimeter and angle adc is 130 degree . Find anglebac

Answer 1

diameter makes 90 degree at the circumference of the circle. in cyclic quadrilateral opposite angles sum up to 180 therefore angle opposite to D which is Angle B will be 50 degrees. now in triangle ACB ,angle ACB will be 90 degree. tharefore applying angle sum property in triangle ACB will give me angle BAC which is equal to 40 degree. degree