The legnth is irrelivant
we know that
Circumference=2 times pi time radius
c=40
40=2 times pi times radius
divide both sides by 2
20=pi times radius
divide both sides b pi
20/pi=radius
the radius is 20/pi cm or aproximately 6.366199048 cm
-2(2b-3)
Multiply the bracket by -2
Whenever multiplying a -negative number with a -negative number= + positive number.
(-2)(2b)(-2)(-3)
-4b+6
Answer: -4b+6
Answer:

Step-by-step explanation:
Cross multiply, isolate the variable, and divide by the coefficient to solve.

Plug back in to check.

To calculate the relative vector of B we have to:
![P_B=\left[\begin{array}{ccc}3\\3\\-2\\3/2\end{array}\right]](https://tex.z-dn.net/?f=P_B%3D%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D3%5C%5C3%5C%5C-2%5C%5C3%2F2%5Cend%7Barray%7D%5Cright%5D)
The coordenates of:
, with respect to B satisfy:

Equating coefficients of like powers of t produces the system of equation:

After solving this system, we have to:

And the result is:
![P_B=\left[\begin{array}{ccc}3\\3\\-2\\3/2\end{array}\right]](https://tex.z-dn.net/?f=P_B%3D%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D3%5C%5C3%5C%5C-2%5C%5C3%2F2%5Cend%7Barray%7D%5Cright%5D)
Learn more: brainly.com/question/16850761
Area of a circle is

. The first one, a, the radius squared is 8*8=64. So

. If you multiply in pi as 3.14, you'll have 200.96 square inches. The second one, b, the radius squared is 10*10=100. So

square kilometers. If you multiply in pi as 3.14 you'll have 314 square kilometers. The third one, c, the radius squared is 14*14=196. So

. Or you could multiply in pi as 3.14 to get 615.44 yd squared. For the last one, d, the radius squared is 22*22=484 cm. Therefore,

, or multiply in 3.14 for pi to get 1519.76 cm squared. There you go!