Question

prove that the opposite angles of a circular quadrilateral are always supplementary
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Answer 1

Answer:

The sum of the angles in each of the triangles is 180 degrees.  Likewise, (a+d) and (b+c) are the measures of opposite angles, and we can just rearrange the equation to see that (a+d)+(b+c) = 180. So, indeed, we see that the opposite angles in a cyclic quadrilateral are supplementary.

Answer 2

Answer:

The sum of the angles in each of the triangles is 180 degrees. ... Likewise, (a+d) and (b+c) are the measures of opposite angles, and we can just rearrange the equation to see that (a+d)+(b+c) = 180. So, indeed, we see that the opposite angles in a cyclic quadrilateral are supplementary.

Step-by-step explanation: