Answer:
Part 1) The measure of angle A is 
Part 2) The length side of a is equal to 
Part 3) The length side of b is equal to 
Step-by-step explanation:
step 1
Find the measure of angle A
we know that
The sum of the internal angles of a triangle must be equal to 180 degrees
so

substitute the given values



step 2
Find the length of side a
Applying the law of sines

substitute the given values



step 3
Find the length of side b
Applying the law of sines

substitute the given values



Mean is adding all the numbers then dividing the answer you go from the numbers.
The answer is 403, just try simple long division.