The diagram below is of a dance floor in the shape of a trapezoid. The diagram was drawn using a scale factor
of 1 centimeter to 8 yards.
In the diagram shown, assume each square on the grid
is 1 centimeter in length.
What is the area, in square yards, of the actual dance
floor?

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.