Practice and Problem-Solving Exercises

A Practice

See Problem 1.

Algebra Lines that appear to be tangent are tangent. O is the center of each circle. What is the value of x?

  1. A circle with center O has radius lines x degrees apart. Rays of a 60 degree angle meet each radius line on the circle.
  2. A triangle has a side as diameter of a circle with center O, with another side tangent to the circle. The other angle inside the circle is x degrees, and the angle outside the circle is 43 degrees.
  3. A triangle has a vertex at center O of a circle, with one side tangent to the circle, and outside angle x degrees. A line from the point of tangency to the intersection of the other side and the circle forms a 60 degree angle at the point of tangency.

See Problem 2.

Earth Science The circle below represents Earth. The radius of Earth is about 6400 km. Find the distance d to the horizon that a person can see on a clear day from each of the following heights h above Earth. Round your answer to the nearest tenth of a kilometer.

A right triangle has a vertex at center E of a circle, with right angle at the point of tangency. One leg measures r, the radius of the circle, the tangent leg measures d, and the hypotenuse has segment r inside the circle and segment h outside.

  1. 5 km
  2. 1 km
  3. 2500 m

See Problem 3.

Algebra In each circle, what is the value of x, to the nearest tenth?

  1. A right triangle has a vertex at the center of a circle, with right angle at the point of tangency. One leg measures x, the radius of the circle, the tangent leg measures 14, and the hypotenuse has segment x inside the circle and segment 10 outside.
  2. A right triangle has a vertex at the center of a circle.
    Image Long Description
  3. A right triangle has a vertex at the center of a circle.
    Image Long Description

See Problem 4.

Determine whether a tangent is shown in each diagram. Explain.

  1. A triangle has a vertex at the center of a circle with a side measuring 5 as the radius of a circle, a side measuring 16 passing through the circle, and a side measuring 15.
  2. A triangle has a vertex at the center of a circle with a side measuring 2.5 as the radius of a circle, a side measuring 6.5 passing through the circle, and a side measuring 6.
  3. A triangle has a vertex at the center of a circle with a side measuring 6 as the radius of a circle, a side measuring 10 passing through the circle, and a side measuring 8.

See Problem 5.

Each polygon circumscribes a circle. What is the perimeter of each polygon?

  1. A quadrilateral circumscribes a circle, with top side divided into segments of 8 centimeters and 16 centimeters, from left to right, and bottom side divided into segments of 6 centimeters and 9 centimeters, from left to right.
  2. A quadrilateral circumscribes a circle, with left side measuring 3.7 inches, bottom side 3.6 inches, and right side 3.4 inches. The top side is divided into two segments, the one on the right measuring 1.9 inches.

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Table of Contents

Prentice Hall Geometry Chapter 1 Tools of Geometry Chapter 2 Reasoning and Proof Chapter 3 Parallel and Perpendicular Lines Chapter 4 Congruent Triangles Chapter 5 Relationships Within Triangles Chapter 6 Polygons and Quadrilaterals Chapter 7 Similarity Chapter 8 Right Triangles and Trigonometry Chapter 9 Transformations Chapter 10 Area Chapter 11 Surface Area and Volume Chapter 12 Circles Skills Handbook Reference Visual Glossary Selected Answers Index Acknowledgments