Answer:
900 sq ft
Step-by-step explanation:
The area of a trapezoid is (Base 1 + Base 2) * height/2. So to plug the numbers in...
(30+60)20/2
90*20/2
1800/2
900 sq ft
Margin error of a sample mean is given by

where σ is the standard deviation,

is the critical value and n is the sample mean.
So beside the given standard deviation, we're supposed to know the sample size and critical value to answer this question.
It’s is D subtract 12 from both sides of the equation
The first one: take 180-135=45. Angle bc is equal to angle fe so then you would take 180-81-45=54. So if 54 is your answer for angle cd then the arc from CFD would be 360-54=306 degrees I believe.