PLEASE HELP! (If you don’t know it please don’t answer)

What is the best approximation for the area of a circle with a radius of 4 m ? use 3.14 to approximate pi

Ariana starts with 100 milligrams of a radioactive substance. the amount of the substance decreases by 20% each week for a number of weeks, w. the expression 100(1−0.2)w finds the amount of radioactive substance remaining after w weeks. which statement about this expression is true? a) it is the difference between the initial amount and the percent decrease. b) it is the difference between the initial amount and the decay factor after w weeks. c) it is the initial amount raised to the decay factor after w weeks. d) it is the product of the initial amount and the decay factor after w weeks.

You are a male who just graduated from college with a bachelor's degree. you have a job paying $50,780.00/yr. a. how does your salary compare to the yearly median earnings for a male with a bachelor's degree? b. what is the difference between the yearly median earnings for a male with a bachelor's degree compared to a male who does not attend college after earning a high school diploma?