PLEASE HELP I HAVE 15 MINUTES LEFT HELP HELP PLEASE

The brain volumes (cm cubed) of 50 brains vary from a low of 904 cm cubed to a high of 1488 cm cubed. use the range rule of thumb to estimate the standard deviation s and compare the result to the exact standard deviation of 175.5 cm cubed, assuming the estimate is accurate if it is within 15 cm cubed

Find the constant of variation for the relation and use it to write an equation for the statement. then solve the equation.

The area of square garden is 300m squared. how long is the diagonal?