https://photomath.net/s/6O312e
^ that link will show you step by step and explain it, rather than writing a whole paragraph, Hope that helps:)
Answer: In degrees , The measure of 
In radians , the measure of
.
Step-by-step explanation:
We know that the formula for length of arc is given by :-
, where
= Central angle subtended by arc.
r= radius of the circle.
As per given , we have
Radius of circle : r=7 m
Length of arc : l= 8 m
Substitute these values in the above formula , we get
Hence, the measure of
.
To convert it into degrees we multiply it with 
The measure of 


Hence, the measure of 
670,130,000 Km or 416,399,477 Miles apart
So the area the circle is 615.44 and the equation to solve it is 2(3.14)r^2