Answer:
A. 76
Step-by-step explanation:
Angle A is half the difference between the measures of arc DE and BC.
m∠A = (1/2)(DE -BC)
20 = (1/2)(116 -BC) . . . . substitute the given values
40 = 116 -BC . . . . . . . . multiply by 2
BC = 116 -40 . . . . . . . . add BC -40
BC = 76
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<em>Comment on intersecting secants</em>
When the secants intersect <em>inside</em> the circle, the angle where they cross is half the <em>sum</em> of the intercepted arcs. When they intersect <em>outside</em> the circle (as here), the angle where they meet is half the <em>difference</em> of the intercepted acs.
Sometimes it is easier to remember two related relationships than it is to remember just one of them.
The answer is 3y-7.hope this helps
