1. ## 7 problems on referance angles, radian measures, etc!

Could someone please show me how to do the following problems. i don't understand what you do at all. THANKS

1. change

-3pi
----
4
to degree measure

2. change 405 to radian measure in terms of pi

3. find one positive angle and one negative angle that are coterminal with an angle measuring 225

4. find the reference angle for

5pi
---
8

5. find the length of an arc to the nearest tenth that intercepts a central angle of 32 in a circle of radius 11 cm.

6. a sector has a central angle of .8 radians and a radius of 7.5 cm. find the area of the sector to the nearest tenth.

7. a flashlight has a range of 100 feet and casts its beam through an angle of 100 degrees. to the nearest 100 square feet, what area is illuminated by the flashlight?

2. Originally Posted by mathgrl
Could someone please show me how to do the following problems. i don't understand what you do at all. THANKS

1. change

-3pi
----
4
to degree measure

2. change 405 to radian measure in terms of pi

To convert $x_{rad}$ radians to degrees:

$x_{deg}=\frac{180}{\pi}x_{rad}$

To convert $x_{deg}$ degrees to radians:

$x_{rad}=\frac{\pi}{180}x_{rad}$

RonL

3. Originally Posted by mathgrl
5. find the length of an arc to the nearest tenth that intercepts a central angle of 32 in a circle of radius 11 cm.
$
$A_{sector}=\frac{\mbox{arc length}\times \mbox{radius}}{2}$