A certain radioactive isotope has a half-life of 4.28 minutes. If we initially have 7168 grams of this substance, how many half-lives will pass until 7 grams remain? Your answer should be a whole number.

Write each expression in exponential form and find its value. 2 x 2 x 2 x 2

Thales was an ancient philosopher familiar with similar triangles. one story about him says that he found the height of a pyramid by measuring its shadow and his own shadow at the same time. if the person is 5-ft tall, what is the height of the pyramid in the drawing?

Which of the following circles have their centers on the x-axis? check all that apply.