if δxyz is dilated by a scale factor of 3 about point y, which of the following is true about a line a prime y prime?

triangle xyz is shown with line ya running vertically through the center of the figure.

line a prime y prime is perpendicular to line ay.
line a prime y prime is parallel to line ay.
line a prime y prime passes through the center of dilation.
line a prime y prime intersects with point x′.

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.