Normalcdf(78, 82, 80, 8/√(64)) = 0.9544997361
The standard deviation of the sample mean will be 8/√64 = 1, so you are asking for the probability that the value will be within 2 standard deviations of the mean. This is a number most statistics students are asked to memorize.
Your probability is about 0.9545.
The answer is 24m^2 i just finished that test and that was the answer.<span />
We know that
[the area of semicircle]=pi*r²/2
for r=3.5 units
[the area of semicircle]=pi*3.5²/2---> 19.24 units²
[the area of the triangle]=b*h/2
b=7 units
h=3 units
[the area of the triangle]=7*3/2-----> 10.5 units²
the area of the figure=19.24+10.50----> 29.74 units²----> 29.7 units ²
the answer is
29.7 units ²