Answer:
At t=1, Rate of Change=-36.86
At t=10 hours, Rate of Change =-0.0088
Step-by-step explanation:
The function which describes the number of facts of a certain type which are remembered after t hours is given as:

To determine the Rate of Change at the given time, we first look for the derivative of f(t).
Applying quotient rule:

At t=1

=-36.86
At t=10 hours

=-0.0088
Answer:
≈39.27 units
Step-by-step explanation:
To find the area of a semi circle, you use the formula for finding the area of a circle, which is 
, and then you divide that by 2 since it is half of a circle.
In this case, 
≈ 78.54
= 39.27
Yes it is because all fractions are rationals