Consider what radians are.
A complete circle is said to have #2pi# radians (if anyone asks why then say that it's made to fit the system of unit circles, circumference #c=2pir# with #r=#unit means #c=2pi# making trigonometric equations easier)
Now, a complete circle is also #360^o#.
So that means, #360^o=2pi^cl#
I'm using a "#l#" here because we don't know how exactly they're related, but we know that they're directly related this way.
Rearrange the equation and we get #l=360^o/{2pi^c#
Now, we need to find the value of radians for a #1400^o#. Let's say we already found that it equals this #x^c# (that "c" on top implies that the number we're talking about here is radians, you might have noticed the "o" on top of the degrees by now)
So that means #1400^o=x^cl#, which can be re-written as #l=1400^o/{x^c}#
It seems like we got two equations for #l#, so let's equate the two, meaning we get
#1400^o/{x^c}=360^o/{2pi^c}#
Rearranging, I get
#{1400^o*2pi^c}/360^o=x^c#
Now, this is why I'm happy calculator exists, which means if you used one here, you'd get #x^c=24.43460952792061^c#, or more simply #x^c=24.4346^c#
Now, this is the number of radians we have. We're asked to say how many #pi#'s are there (but not a lot of pies sadly).
Now, if I had three chocolate bars, and had to distribute them among 2 people(excluding me), how many would each person have? Well, each person would have 1.5 chocolate bars.
Same thing here, we'll divide the value of #x^c# we got with #pi# people (of course #pi# people can't exist. Three people? yes, 3.1415 people? That'd be interesting)
That means #x^c=7.7777pi^c#
