Question

The area of a circle (A) is given by the formula A=r^2 where r is the circle's radius. The formula to find r is______ . If (A)=54 centimeters ^2 and pi=22/7, r is ______ centimeters.
Space #1
A. (A/pi)^1/2
B. A^2/pi
C. pi/A

Space #2
A. 4.15
B. 2.33
C. 17.2

Answer 1

Answer: (A)   and   (A)

Step-by-step explanation:

$A=\pi \cdot r^2\\\\\dfrac{A}{\pi}=r^2\\\\\sqrt{\dfrac{A}{\pi}}=r\ \rightarrow \ \bigg(\dfrac{A}{\pi}\bigg)^{\dfrac{1}{2}}\\\\\\\\r=\sqrt{\dfrac{A}{\pi}}\\\\.\ =\sqrt{\dfrac{54\cdot 7}{22}}\\\\.\ =\sqrt{\dfrac{27\cdot 7}{11}}\\\\.\ =\sqrt{\dfrac{189}{11}}\\\\.\ =\sqrt{17.1818}\\\\.\ =4.15$