Protons is the answer that makes the most sense
You do mass divided by density
The slope formula is y=mx+b. Y is a variable. m is the actual slope. It tells you how much the x will move. For example, if a slope was 2x, x would move up 2 and over 1. If the slope was 1/2 x, x would move up 1 and over 2. A way to remember slope is rise over run. X is a variable. B is a point on the y-intercept that is will the line will start. An example is y=x+3. The y-intercept is 3 and x would move up one and over one.
3.9 is the estimated square root of 15 to one decimal place
