# phase angle

Discussion in 'Homework Help' started by navyman, Sep 26, 2006.

1. ### navyman Thread Starter New Member

Sep 26, 2006
7
0
There are 3 sides to a triangle.
One side is 5"
One side is 4"
One side is 3"

The phase angle (Theta) formula is:
equals tan-1 4/3
How did they get the phase angle of 53.13
I am putting it in the calculator wrong.

I am trying to get the phase of 6280(XL) over 5000(R)

Is it tan-1 6280/5000
The answer key says it's .898

???

I seem to be missing something.

2. ### navyman Thread Starter New Member

Sep 26, 2006
7
0
There are 3 sides to a triangle.
One side is 5"
One side is 4"
One side is 3"

The phase angle (Theta) formula is:
equals tan-1 4/3
How did they get the phase angle of 53.13
I am putting it in the calculator wrong.

I am trying to get the phase of 6280(XL) over 5000(R)

Is it tan-1 6280/5000
The answer key says it's .898

???

I seem to be missing something.

3. ### hgmjr Moderator

Jan 28, 2005
9,030
214
This answer is expressed in terms of degrees.

This answer is expressed in radians. You need to look into how to convert between degrees and radians.

Some calculators can be switched between providing trig answers in radians or degrees. You may need to look at your calculator's owner's manual to see if it has that feature. If not, there is a formula for the conversion from one to the other.

hgmjr

4. ### hgmjr Moderator

Jan 28, 2005
9,030
214
The above answer is expressed in degrees.

Some calculators can be set to calculate trig answers in radians or degrees.

Suggest you consult your calculator's owner's manual to see if your calculator has that feature.

It may be worthwhile to look up the conversion factor that is used to convert radians to degrees and back since it is a piece of knowledge that will serve you well later on in your career.

hgmjr

5. ### navyman Thread Starter New Member

Sep 26, 2006
7
0
Thank You !!
My frustration was caused by my lack of not paying attention to what mode my calcautor was in.

6. ### hgmjr Moderator

Jan 28, 2005
9,030
214
That was what I had suspected to be the case.

So glad you were able to get things cleared up.

hgmjr

7. ### roshankshanbhag New Member

Jul 8, 2009
3
0
@navyman

the tan-1 (4/3) =53.13 is expressed in degrees

@ hgmjr

to convert this degree into radians.....either change the mode on your calculator from DEG to RAD or quite simply use the below formula :
--------------------------------------------------------------
Degrees to radians = x*(2∏/360) where x is expressed in degrees
--------------------------------------------------------------

If you are using the popular CASIO fx 82 or 100 series calculator....you will have to calculate the sum or product and then hit the tan-1 ( SHIFT+TAN) key to get the result.

one quick and dirty way to find out how to use the calculatoe for trigonometric calculations is to plug in some known values and get expected results Ex: tan 45 =1 , sin 30=0.5, cos 60 =0.5 etc...( check whether hitting the "tan" button and then entering the number 45 gives you the result or the other way around)