Answer:
D 81 pi units^2
Step-by-step explanation:
The circumference of a circle is given by
C = 2 * pi *r
18 pi = 2 * pi *r
Divide each side by 2 * pi
18 pi / (2 pi) = 2 pi * r/ (2 pi)
9 = r
Now we can find the area. Area is given by
A = pi r^2
A = pi * 9^2
A = 81 pi units^2
Okay so this is going to be confusing but work from right to left. since you can’t do 0-5, borrow from the one next to the zero on the top, cross out the one and put zero and add a one on top of the zero which makes it 10. now you can do 10-5 to get 5. put the five down below the line. next solve the second column of numbers ( second to the right). since you cannot do 0- 3, like the last one, you have to borrow from the 7 over to the left. take one from there and cross the seven out and put a six. now you have 10-3 which is 7. put the 7 down. now do move to the next column and do 6-2 to get 4. put the four down below the line. move to the next column and do 2-2 to get 0. put the zero down below the line. lastly, we know the answer has to be negative so we are going to do 2-7 to get -5. put -5 down below the line and together to get the answer -502,275. i know that was very confusing but i hope it helped a little bit. i added a picture to clarify a little
Let's say you have the equation
5x + 3y = 11
You are asked to test the ordered pair (1, 2) to see if it is a solution of the equation. A solution of the equation will make the equation a true statement. The ordered pair (1, 2) has 1 as its x-coordinate and 2 as its y-coordinate.
Substitute 1 for x and 2 for y in the equation. Then work it out to see if it is a true statement.
5x + 3y = 11
5(1) + 3(2) = 11
5 + 6 = 11
11 = 11
Since 11 = 11 is a true statement, the ordered pair (1, 3) is a solution of the equation.
21^2/0.219 = 2013.69863
2 significant figures are the 20, so the answer is 2000