algebra word problem

Question

If A = 1,386 square centimeters and π = 22 , find r. A = Πr² (Transpose the forumla before solving for r.)

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Answer 1

A=(pi)*r^2

1386=(22/7)*(r^2)

multiply both sides by (7/22)

(7/22)(1386)=(7/22)(22/7)(r^2)

simplify, 1386 is divisible by 22, 1386/22=63

7*63=r^2

441=r^2

take the square root of both sides

√441=√r^2

21=r

r=21 cm

or,...

A/(22/7)=r^2

7*A/22=r^2

7*1386/22=r^2

simplify if you like first or multiply and then divide

9702/22=r^2

441=r^2

r=21 cm again if you need to transpose first