Ihave a math exam tomorrow! me cover these concepts? how to find the volume of a hot air balloon if you know the density and the mass how to find the center and radius of a circle by looking at the equation what formula to use to find out the measure of an angle on a quadrilateral

Hot air balloon volume: density isgiven by the formula:     with mass  and volume  .if you want to find the volume, we can make volume the subject of the density formula.multiply both sides by v so that the v in the denominator on the right side cancels out.        divide both sides by density.    mass divided by density will get you volume.you could also do this by dimensional analysis.e.g., balloon with volume of  and a density of  .     this means that you want to cancel out the units.    the units of kg cancel out and you are left with 600m³/0.85, which is approx 706 m³it's the exact answer if you did as mass divided by density, just not as much memorizing. you just focus on canceling out units.======center and radius of circle from eqn: standard form of a circle:     the center is at  and radius is  . if you rearrange equations of circles, you can identify using this form.e.g. for the circle    we can rewrite as    so h = -3, k = 1, and the radius is 7e.g. the circle    has center at (2,-3) and radius of  . (2 can be written as )======measure of angle in a quadrilateral  angles in a quadrilateral all sum up to 360 degrees.if a quadrilateral has angles  ,  ,  and  , then    if the quadrilateral is inscribed in a circle, then angles in the quadrilateral opposite to each other sum to up 180 degrees.