What is the area of a circle with a 13 ft radius

I’m stuck on this i don’t understand.

Achemist has 200 ml of a 10% sucrose solution. she adds x ml of a 40% sucrose solution. the percent concentration, y, of the final mixture is given by the rational function: the chemist needs the concentration of the final mixture to be 30%. how many milliliters of the 40% solution should she add to the 10% solution to get this concentration?

Angle mno is s rotated 180 degrees counterclockwise about the origin to form angle m’n’o’. which statement shows the measure of angle m’n’o’?