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: Identify the strategy that the student below used to find the measure of
$${BA}$$
. Then, describe a different method for finding this value, describing how you know that the two triangles are dilations of one another.
[IMG]


aligns: no