Answer:
approximately 42.05
Step-by-step explanation:
We know that the distance formula is
, so if we use (3,8) as point 2 and (21, -30) as point 1 (note that these are interchangeable), we know that
x₂=3
y₂=8
x₁=21
y₁=-30
Then, we can plug it into the formula to get 
Answer:
<em>P = 44 m</em>
Step-by-step explanation:
Attached in file.