The document defines key terms related to angles and radians: 1) A unit circle is a circle whose radius is equal to one unit and whose center is at the origin. 2) A radian is a measure of a central angle subtended by an arc whose length is equal to the radius of the circle. 3) One full revolution equals 2π radians.

1. (ACTIVITY#1)PRICE TAG!
The set of all points in a plane that are equidistant from
a fixed point in the plane.
A line segment that joins the center of a circle to a point
on the circle
A line segment that joins the center of a circle to a point
on the circle

3. Starri
ng
* Angles

Andintroducing…
* π Radians
* Degrees
* The Converter

5. Define Unit Circle
Define radian measure of an angle
Convert from degree measure to
radian measure & vice versa

6. Pre-ActivityA. (ConnectMetoYou!)
A circle whose radius is equal to
one unit and whose center is at the
origin
Measure of a central angle
subtendedby an arc whose length
is equal to the radius of a circle
One of the two rays of an angle that
is kept stationary
One of the two rays of an angle that
is rotated about the common
endpoint
Terminal Side
Initial Side
Unit Circle
Radian

7. Pre-ActivityB. (ChangemyWorld!)
Convert to degree measure
2π rad =
π rad = º
π/3 rad = º
Convert to radian measure
180 º
360 º
270 º

8. Angle-
formed by rotating a ray
about its endpoint (vertex)
Initial Side Starting position
Terminal Side
Standard Position
Initial side on positive x-axis and
the vertex is on the origin
Ending position

9. 1 Radian = measure of central angle of a circle whose
rays subtend an arc whose length is equal to the radius
of the circle.
Arc length “s” = radius when  = 1 radian
Length BC on AB = cm
m AB = 4.31 cm
A B
C

10. C =
0
=3.14
2= 6.28
Therefore, we can say
that 1 full revolution = 2
radians.
1
0.5
-0.5
-1
-2 -1 1 2

12. A circle whose radius is equal to
one unit and whose center is at the
origin
Measure of a central angle
subtendedby an arc whose length
is equal to the radius of a circle
One of the two rays of an angle that
is kept stationary
One of the two rays of an angle that
is rotated about the common
endpoint
Terminal Side
Initial Side
Unit Circle
Radian

13. Convert to degree measure
2π rad = 360 º
π rad = 180 º
π/3 rad = 60º
Convert to radian measure
180 º= π rad
360 º= 2π rad
270 º= 3/2π rad

14. Power Group!