Which equation could be used to solve for the measure of angle r? circle n is shown with a quadrilateral opqr inscribed inside it. angle o is labeled x degrees. angle p is labeled y degrees. angle q is labeled z degrees. angle r is labeled w degrees. w − (x + y) = 360 w + x + y = 360 w + z = 180 w + y = 180

The opposite angles in a cyclic quadrilateral are supplementary.

That's relatively easy to understand. Consider one of the diagonal chords. The central angle to that chord is the twice the measure of one quadrilateral angle and 360 minus the central angle is twice the measure of the opposite quadrilateral angle. So the two add to 180.

In our problem P=y is opposite R=w

w + y = 180 degrees

Last choice

1) is right

step-by-step explanation:

not only in mathematics, scientific proof also are required in the other field of science. also maths proofs are of particular structure, containing steps and logics. so proving is like doing science, it is science. that's why it is important to prove. 

an inaccurate proof leads to errors, or stating results that are not accurate.  which wil mess the probelm up you dont want this