Question

Assume that lines that appear to be tangent are tangent. O is the center of the circle. What is the value of x?

Answer 1

9514 1404 393

Answer:

x = 20, or 125

Explanation:

We cannot tell the angle x is intended to refer to. So, here are two answers. Choose the one you think applies.

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The triangle that includes both marked angles is a right triangle. (The tangent meets the circle at right angles to the radius.) So, the angle x° at the external point is the complement of the marked central angle.

x° = 90° -70°

x = 20

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If x° is referring to the exterior angle associated with the isosceles triangle within the circle, then its measure is the supplement of the interior base angle of that triangle. It is ...

x° = 180° -(180° -70°)/2 = 90° +70°/2

x = 125