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The measure of an angle formed by two tangents to a circle is 80°. The radius of the circle is 8

centimeters. How far is the vertex of the angle from the center of the circle to the nearest centimeter?

1 Answer

4 votes

Answer: So the vertex of the angle is located at the center of the circle, which is 8 centimeters away from the nearest centimeter.

Explanation:

Let O be the center of the circle, and let A and B be the points of tangency of the two tangents with the circle. Since OA and OB are radii of the circle, they have the same length of 8 centimeters.

Let C be the vertex of the angle formed by the two tangents. Since the tangents are perpendicular to the radii at the points of tangency, we have that angle AOC = angle BOC = 90 degrees.

Since the measure of the angle formed by the two tangents is 80 degrees, we have that angle AOB = 180 - 80 - 80 = 20 degrees.

Let D be the foot of the perpendicular from C to line AB. Then angle OCD = 90 - 20/2 = 80 degrees, so triangle OCD is an isosceles triangle. Therefore, we have that OD = OC = 8 centimeters.

Finally, since triangle OCD is a right triangle, we can use the Pythagorean theorem to find the length of CD. We have:

CD^2 = OD^2 - OC^2 = 8^2 - 8^2 = 0

Therefore, CD = 0 centimeters.

So the vertex of the angle is located at the center of the circle, which is 8 centimeters away from the nearest centimeter.

answered
User Ersin Er
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