The angle tells you the proportion of the circle. So it's just .
Hi, i am studying maths on khan academy and got stuck with a certain problem and i can't find any videos which explain it so i could do with some help please.
When i look up how to do this problem on the internet it says i just do 321/360 * the circumference. simple but i want to know how to work it out the way they have done it in the image. I don't understand how he gets from step 2 to step 3, how he gets the 321/360 to 107/6. so the question isn't really geometry but i didn't know where else to put it.
"A circle with circumference 20π has an arc with a 321∘ central angle. What is the length of the arc?"
Simplifying fractions involves looking for common factors in both the numerator and denominator and canceling them out. So for example:
Don't be confused by the fact that in my previous post I showed the factor in front of the fraction as opposed to being in the numerator:
Of course, you don't have to do it that way. You can go ahead and multiply to get
Then it should be obvious that both are divisible by 10:
And, since both of those are even, they are divisible by 2:
It is not quite so obvious but those are both divisible by 3: .
That's not algebra- that's arithmetic.