Why is circle 1 similar to circle 2?

circle 1: center (−1, 10) and radius 4.8

circle 2: center (−1, 10) and radius 1.2

circle 1 is congruent to circle 2.
circle 1 and circle 2 have the same center.
circle 2 is a dilation of circle 1 with a scale factor of 3.6.
circle 1 is a dilation of circle 2 with a scale factor of 4.

If mary had 320 toy cars and she gave her friend 50 cars and then she gave her brother 72 more cars how much toy cars would mary have left ● explain with proper details

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

Find the vertex for the parabola given by the function ƒ(x) = −3x2 − 6x.