Q: What is the area of a circle if the radius is 9 In?

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The area of a circle with a radius of nine centimeters is: 254.5 cm2

The radius is 9 inches because area of circle is pi*9 squared = 81pi square inches and the diameter is twice the radius which is 2*9 = 18 inches

Area = pi * radius^2. radius = diameter / 2, so radius of this circle is 3.Area = 9 * pi (take your favorite value of pi: 3.1416....)

As the area of a circle is pi*radius2 the increase in area is a factor of 32. So tripling the radius gives an increase in area by a factor of 9.

The area increases as the square of the radius (or diameter). So if you double the radius you * 4 (quadruple) the area. Treble the radius, you *9 the area.

Related questions

A circle with a radius of 9 feet has an area of 254.47 square feet.

If you triple the radius of a circle, the area will increase by 9. Area is proportional to the square of the radius.

The area of a circle with a radius of nine centimeters is: 254.5 cm2

A circle with a radius of 9 feet has an area of 254.47 square feet.

The radius is 9 inches because area of circle is pi*9 squared = 81pi square inches and the diameter is twice the radius which is 2*9 = 18 inches

The area is 254.47 in2

The radius is 9 feet.

When you triple the radius of the circle . . . -- The diameter also triples. -- The circumference also triples. -- The area is multiplied by 9 .

The answer is 254.469005cm squared

9

The area increases as the square of the radius (or diameter). So if you double the radius you * 4 (quadruple) the area. Treble the radius, you *9 the area.

Area(A)/ Area(B) = pi*rA2/pi*rB2 = rA2/rB2 = 16/81