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Find the area of a trapezoid with a height of 23, base 1 of 10 and base 2 of 18

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

What is the approximate mark up percentage rate before m equals $1740 marked up from p equals $19,422