mu = 1100 = population mean
sigma = 275 = population standard deviation
x = 1400 = raw score
z = z score
z = (x-mu)/sigma
z = (1400-1100)/(275)
z = 300/275
z = 1.0909090909091 approximately
z = 1.09
Convention is to round to two decimal places so that you can use a Z table to look up the area under the curve (which helps determine probability).
The positive z score is due to Paula's raw score being above the mean.
So to solve you need to set up equations, Using h as the height. So the base is 9 inches more (+9) than 3 times the height (3h) so 3h+9 equals the base. You have the area so you need to plug in the equation for the base and h for height and divide it all by 2. h(3h+9)/2=105. after you solve that and get h by itself you should get h= 7 and the b= 30
= [7+7 <span>÷ 7] + 4.12
= [7+1] + 4.12
= 8 + 4.12
= 12.12
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