Answer:
Step-by-step explanation:
Remember that
Area of Circle =

They told us that for this circle, the area is 
If you put it back into the formula for area of a circle we get:
Area of Circle =

Divide both sides by
.
144 = 
Now we want to solve for r (r = radius).
You need to square root each side


So now we know the radius,
metres
Also remember that
Diameter = 
So,
Diameter = 2 times 12 = 24 metres
Direct variation is y=kx, inverse variation is y=k/x....
-5y=-2x divide both sides by -5
y=2.5x
So this is a direct variation with a constant of 2.5
Answer:
8.3
Step-by-step explanation:
The slope will be the difference between the y-coordinates divided by the difference between the x-coordinates:
then the slope of the line is:
Answer:
The amount of oil was decreasing at 69300 barrels, yearly
Step-by-step explanation:
Given


Required
At what rate did oil decrease when 600000 barrels remain
To do this, we make use of the following notations
t = Time
A = Amount left in the well
So:

Where k represents the constant of proportionality

Multiply both sides by dt/A


Integrate both sides


Make A, the subject

i.e. At initial
So, we have:






Substitute
in 

To solve for k;

i.e.

So:

Divide both sides by 1000000

Take natural logarithm (ln) of both sides


Solve for k



Recall that:

Where
= Rate
So, when

The rate is:


<em>Hence, the amount of oil was decreasing at 69300 barrels, yearly</em>