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)

Explanation:

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