Hi there! The answer is 100πcm^2
The radius of a circle can be found by dividing the diameter by 2. In other words : the radius is half of the diameter.
Therefore, the radius of a circle with a diameter of 20 cm is 10 cm.
The exact area of a circle can be found using the following formula:

In order to find our answer, we need to plug in the data from the question.

Hence, the answer is 100πcm^2.
A because you can have many different results
The answer is the third one.
The way I think through these problems is that where you multiply (-7x), you use addition, and where you use addition (-4), you multiply.
The answers added together will equal the second number, -7, and multiplied will give you the third, -4.
What you had chosen as the answer was close. But 7.53+-0.53 equals positive 7, not negative. However they do round to -4 when multiplied.
The correct answer, -7.53 and 0.53, do equal -7 when added together and equal -4 when multiplied.
If you use a proportion, you'll get:

Then, you use cross products:

Then, you algebraically solve x:

The answer is 5/3 inches , or 1 5/13 inches, or 1.6 repeating.
I hope this helps you
x^2-7x-44
x -11
x +4
(x-11)(x+4)