A$33$-gon $p_1$ is drawn in the cartesian plane. the sum of the $x$-coordinates of the $33$ vertices equals $99$. the midpoints of the sides of $p_1$ form a second $33$-gon, $p_2$. finally, the midpoints of the sides of $p_2$ form a third $33$-gon, $p_3$. find the sum of the $x$-coordinates of the vertices of $p_3$.

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