You have posted 2 separate questions here. Please, next time, separate them with a blank line:
<span>A circle has an area of 81 3.14 units . what is the diameter in terms of 3.14?
I'd prefer you write this as
"</span><span>A circle has an area of 81 pi units . what is the diameter in terms of pi?
Area of a circle = A = pi*r^2. Note that r= diameter / 2. Here, the area is 81 pi square units, or 9^2 * pi square units, which means that the radius is 9 units. The diameter is then 2(9 units) = 18 units.
Your second question, separated from the first, is:
"</span><span>a circle has an area of 81 Pi square units what is the diameter of the circle?"
</span><span>
Use the following formula or formulas: d = 2*r; A = pi*r^2; A = pi*(d/2)^2. Find r first, and then find d.
</span>
Answer:
B. 88.5
Step-by-step explanation:
first we add all the numbers :
(79 +80 +92 +92 +81 +100 +88 +98 +71 + 100+91+90) over 12
= 1062 over 12
= 88.5
[why over 12? because there's 12 numbers]
x^2 = 800. Take the square root of each side.
x = √(800) and -√(800)
