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Given: DR tangent to Circle O.

Ir DB=140, then A=

A)70
B)110
C)140
D)80

The quiz says 140 is wrong, but I don’t know if that’s a problem on the teacher’s end or not, because everyone here says it’s 140

Given DR tangent to Circle O Ir DB140 then A A70 B110 C140 D80 The quiz says 140 is wrong but I dont know if thats a problem on the teachers end or not because class=

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Answer:

I believe the answer is 110.

Answer:

110°

Step-by-step explanation:

In this problem we need to use the Inscribed Angle theorem, which states that an inscribed angle is one-half its subtended arc.

[tex]\angle C=\frac{1}{2}arc(DB)=70\°[/tex]

Then, we use the theorem about a cyclic quadrilateral, which is an inscribed quadrilateral: "the opposite angles in a cyclic quadrilateral are supplementary".

[tex]\angle C + \angle A = 180\°\\\angle A = 180\° - \angle C\\\angle A = 180\° - 70\° \\\angle A = 110\°[/tex]

Therefore, the answer is 110°

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