Finding the angle beta for vector <60,-50,40>

[xtrubambinoxpr]

Homework Statement

Find Beta of <60,-50,40>

Homework Equations

Cosine β = Ay/lAl

The Attempt at a Solution

lAl = 87.74964387

So its arccos(-50/87.75) = 124.62

express to 2 significant figures and it keeps telling me I am wrong. I rounded to 125. kept at 124.62.. etc.

 

[xtrubambinoxpr]

And i got the answer book telling me this

 

[PhanthomJay]

The book answers are clearly expressed to three significant figures. What is your correct response for the angle you determined expressed to two significant figures?

 

[xtrubambinoxpr]

Online it tells me to do 2 sig figs.

 

[xtrubambinoxpr]

The book answers are clearly expressed to three significant figures. What is your correct response for the angle you determined expressed to two significant figures?

And it's 125 degrees

 

[PhanthomJay]

And it's 125 degrees

No, that is three significant figures. What is 124.62 degrees expressed to two significant figures??

 

[xtrubambinoxpr]

No, that is three significant figures. What is 124.62 degrees expressed to two significant figures??

I honestly don't know because it clearly has 3 at 125
How would I make that 2 sig figs

 

[PhanthomJay]

I honestly don't know because it clearly has 3 at 125
How would I make that 2 sig figs

I am not an expert on significant figure rules, but you can find them through Google and other search engines. But here is a hint: 141.635 rounded to four sig figs is 141.6. If rounded to three sig figs it is 142; that same number rounded to two sig figs is 140. And that same number rounded to one sig fig is 100.