standard_description: Use informal arguments to establish facts about the angle sum and exterior angle of triangles, about the angles created when parallel lines are cut by a transversal, and the angle-angle criterion for similarity of triangles. For example, arrange three copies of the same triangle so that the sum of the three angles appears to form a line, and give an argument in terms of transversals why this is so.
problem_activity: Problem 1
Circles
$$A$$
and
$$C$$
are shown below.
[IMG]
Write an equation that describes each of the circles.
Problem 2
Write the equation of a circle whose diameter has endpoints of
$$(-8, 2)$$
and
$$ (2, 2)$$
.
Problem 3
Describe how you could prove that circle
$$A$$
is similar to circle
$$B$$
.
[IMG]


aligns: no