The circumference of a circle of radius
is

So, in your case, the circumference is

The circumference is actually the length of the "perimeter", so the answer to questions 1 and 2 looks the same actually
Https://www.symbolab.com/solver/function-range-calculator
this should help
Whats the problem? i cant solve it w/o the problem doll
Answer:
9. 
10. 
Step-by-step explanation:
9. Given the sequence

In this sequence,

Note that

then the common difference in this sequence is 
You have

then the explicit formula is

10. Given the sequence

In this sequence,

Note that

then the common difference in this sequence is 
You have

then the recursive formula is

The problem is modelled in the first picture shown below
To work out the resultant vector, we modelled the vectors 150N and 75N as triangle AOB is shown in the second picture with AB as the resultant vector.
We use the cosine rule to work out the length AB




(nearest whole number)
The third picture shows the full diagram of the vectors
To work out the direction of the resultant vector, we use the sin rule to find the size of angle A and angle B
Angle A






(rounded to nearest whole number)
Angle B

Direction is 60° toward negative x-axis
Answer: Magnitude 130N and direction 60° toward negative x-axis