The half-life radioactive kind of cobalt is 71 days. If you start with 68,992 grams of it, how much will be left after 355 days?

Five dinosaurs go for a walk and come across some lovely chicken wings. their names are rexy, bronto, steggy, paly, and terry. there are exactly 5 dozen wings(equal enough for each dino to have a dozen right? ); however, terry is on a diet and he only eats 6 wings. if paly eats 2 more than terry, steggy eats 4 more than paly, and bronto and rexy eat the same amount because they are really hungry from not eating all day, how many chicken wings did each dino eat?

Asquare has a side that measures 11 units. what is the area of a circle with a circumference that equals the perimeter of the square? use 3.14 for π, and round your answer to the nearest hundredth. 1519.76 units2 379.94 units2 616.56 units2 154.14 units2

Asap! i'm not good math and i'm lost.