options: Solve real-world and mathematical problems involving area, surface area, and volume.

Prove theorems involving similarity.

Understand and apply the Pythagorean Theorem.

Make geometric constructions.

Understand congruence in terms of rigid motions.

Identify and describe shapes (squares, circles, triangles, rectangles, hexagons, cubes, cones, cylinders, and spheres).

Experiment with transformations in the plane.

Understand similarity in terms of similarity transformations.

Draw and identify lines and angles, and classify shapes by properties of their lines and angles.

Understand congruence and similarity using physical models, transparencies, or geometry software.

Analyze, compare, create, and compose shapes.

Solve real-life and mathematical problems involving angle measure, area, surface area, and volume.

Explain volume formulas and use them to solve problems.

Reason with shapes and their attributes.

Use coordinates to prove simple geometric theorems algebraically.

Draw, construct, and describe geometrical figures and describe the relationships between them.

Apply geometric concepts in modeling situations.

Solve real-world and mathematical problems involving volume of cylinders, cones, and spheres.

Translate between the geometric description and the equation for a conic section.

Visualize relationships between two-dimensional and three-dimensional objects.

Apply trigonometry to general triangles.

Classify two-dimensional figures into categories based on their properties.

Understand and apply theorems about circles.

Find arc lengths and areas of sectors of circles.

Graph points on the coordinate plane to solve real-world and mathematical problems.

Prove geometric theorems.

Define trigonometric ratios and solve problems involving right triangles.
problem_activity: Task
This problem examines equations defining different circles in the $x$-$y$ plane.
Use the Pythagorean theorem to
find an equation in $x$ and $y$ whose solutions are the points on the circle  of radius 2 with center $(1,1)$  and explain why it works.
Suppose $r$ is a positive number and $(a,b)$ a point in the plane.
Use the Pythagorean theorem to
find an equation in $x$ and $y$ whose solutions are the points on the circle of radius $r$ with center $(a,b)$ and explain why it works.


correct_option_index: 18