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Need explanation -- Geometry Unit 9 Circles

Need explanation -- Geometry Unit 9 Circles-example-1
User Laverick
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Answer:

19

Explanation:

Given that Circle O is inscribed in quadrilateral TANG and point of tangency bisects AT. Let's denote the point of tangency as M. Therefore, AM = MT.

Now, we can use the property that the angle subtended by a chord at the center of the circle is twice the angle subtended by the same chord at any point on the circumference of the circle.

Angle AGT = 2 * Angle ANT

Angle AOT = 2 * Angle ANM (Angle subtended by the chord AT at point O)

We know that Angle AGT + Angle AOT = 180 degrees (sum of opposite angles in a cyclic quadrilateral TANGO)

Substituting the above angles in terms of AN and x, we get:

Angle ANT = Angle AGT/2 = (Angle AOT/2)/2

Tan (Angle AGT/2) = GN/AG = 10/AG

Tan (Angle AOT/4) = AM/AO = (AT/2)/r (where r is the radius of the circle)

AT = AG + GN + TG = AG + 10 + 12 = AG + 22

r = AO = OM = AT/2 - x = AG/2 + 11 - x

Using the property that the sum of interior angles in a quadrilateral is 360 degrees, we can write:

Angle AGT + Angle ANT + Angle GNA + Angle TGA = 360 degrees

2 * Angle ANT + 2 * Angle ANM + Angle GNA + Angle TGA = 360 degrees

Substituting the above angles in terms of AN and x, we get:

2 * Angle AGT/2 + 2 * Angle AOT/4 + Angle GNA + Angle TGA = 360 degrees

2 * Tan^-1 (10/AG) + 2 * Tan^-1 [(AT/2)/r] + Tan^-1 (AN/AG) + Tan^-1 (AN/TG) = 180 degrees

Substituting the values of AG, AT, GN, TG, r, and x, we get:

2 * Tan^-1 (10/AG) + 2 * Tan^-1 [(18/2)/(18/2 + 2x)] + Tan^-1 (AN/AG) + Tan^-1 (AN/12) = 180 degrees

Solving this equation for AN, we get:

AN = 2.15 * AG

Substituting AG = 8.88 (approx.), we get:

AN = 19.0 (approx.)

Therefore, AN is approximately 19.0.

User Turtles Are Cute
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