Answer:
The mean is usual
Step-by-step explanation:
We have that the mean (m) is equal to 21, the standard deviation (sd) = 1.31 and the sample size (n) = 64
They ask us for P (x <20.5)
For this, the first thing is to calculate z, which is given by the following equation:
z = (x - m) / (sd / (n ^ 1/2))
We have all these values, replacing we have:
z = (20.5 - 21) / (1.31 / (64 ^ 1/2))
z = -3.05
With the normal distribution table (attached), we have that at that value, the probability is:
P (z <-3.05) = 0.0002
The mean is usual because P (x> 20.5) = 1 - P (x <20.5) = 1 - 0.0002 = 0.9998 is a fairly high probability.
The sum of the angles of any triangle is 180 degrees, so we get the equation:

x = 6
Hope that helps!
Answer:
162
Step-by-step explanation:
Seven multiplied by ten to the third power
Answer:
if it is put into a equation this would be it
2(x^2+6x+9) - (1.57)(x^2+6x+9)
Step-by-step explanation:
(x+3)(2x+6) - 1/2(3.14)(x+3)(x+3)
(2x^2+6x+6x+18) - 1/2(3.14)(x^2+3x+3x+9)
(2x^2+12x+18) - 1/2(3.14)(x^2+6x+9)
2(x^2+6x+9) - (1.57)(x^2+6x+9)
2(x^2+6x+9) is the rectangle at the bottom
(1.57)(x^2+6x+9) is the semicircle that is taking out of the shaded area