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: Problem 1
This slider
shows a triangle dilated using different scale factors.
Slide the point to the right and to the left.
What do you notice as you change the scale factor of this figure?
Problem 2
Below is
$${{\overline{BC}}}$$
, with a length of
$$5$$
units and its dilation about the point
$$O$$
,
$${\overline{B'C'}}$$
.
[IMG]
What is the scale factor used to dilate
$${{\overline{BC}}}$$
?
What is the relationship between
$$\overline{BO}$$
and
$$\overline{B'O}$$
? Why does this make sense?
Problem 3
Dilate the following figure using constructions about center
$$A$$
by a factor of
$$3$$
.
[IMG]


aligns: no