standard_description: Derive using similarity the fact that the length of the arc intercepted by an angle is proportional to the radius, and define the radian measure of the angle as the constant of proportionality; derive the formula for the area of a sector.
problem_activity: Reflect angle
$${\angle FGH}$$
over
$${\overleftrightarrow{JK}}$$
.
Describe the relationships between the line segments and angle of the image and the pre-image.
Describe the relationship between the distance of corresponding points to the line of reflection.
Describe the relationship between the line of reflection and line segments formed by corresponding points.
[IMG]


aligns: no