If the radius of a circle is 15 cm, what is the diameter?
15 cm
30 cm
45 cm
7.5 cm

Which system of linear inequalities is represented by the graph?

The average human heart beats 1.15 \cdot 10^51.15⋅10 5 1, point, 15, dot, 10, start superscript, 5, end superscript times per day. there are 3.65 \cdot 10^23.65⋅10 2 3, point, 65, dot, 10, start superscript, 2, end superscript days in one year. how many times does the heart beat in one year? write your answer in scientific notation, and round to one decimal place.

The lines shown below are parallel. if the green line has a slope of -1, what is the slope of the red line?