“Find the missing side lengths, leave your answer as radicals in the simplest form” please show work

Really need on these. i have no idea what to do

Fiona races bmx around a circular dirt course. if the radius of the course is 70 meters, what is the total distance fiona covers in two laps of the race? a. about 30,772 meters b. about 15,386 meters c. about 879.2 meters d. about 439.6 meters e. about 219.8 meters23 points hurry

An equation of the line tangent to y=x^3+3x^2+2 at its point of inflection is