Brian made a circular coaster from a square piece of wood as shown in the diagram below. The length of the square is 12cm. In terms of pi, what is the circumference, in centimeters, of the circular coaster?

The weight of a radioactive isotope was 96 grams at the start of an experiment. after one hour, the weight of the isotope was half of its initial weight. after two hours, the weight of the isotope was half of its weight the previous hour. if this pattern continues, which of the following graphs represents the weight of the radioactive isotope over time? a. graph w b. graph x c. graph y d. graph z