Question

If a circular plate has a diameter of 9 inches. What is the area of the plate

Answer 1

Answer: The area of the circular plate is: " 63.59 in² " .
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Note:
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diameter, "d" = 9 in. (given).

radius, "r" = "d/ 2 " = "(9 inches) / 2 " = 4.5 in.
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Area of a circle, "A" :

A =
`\pi` * r² ;

in which: "A = Area of circle ("plate"); in units of "square inches"; or "in² " ;

"
`\pi` = 3.14 " {approximation we shall use} ;

"r = radius = 4.5 in." ;
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Plug in our known values to solve for the area, "A" :

A = (3.14) * (4.5 in)² ;

A = (3.14) * (4.5)² * (in²) ;

A = (3.14) * (4.5) * (4.5) * (in²) ;

A = 63.585 in² ; round to: " 63.59 in² " .
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Answer 2

The meaning of the area is the measurement of a surface in this case a circle, which can be find by using the formula A=πr^2, where r is equal to the radius of the circle.

In this exercise is given that a circular plate has a diameter of 9 inches and it is asked to find its area, as previous said the only way to find the area of a circle is by using the formula A=πr^2, but on this case the radius is not given. Meaning that you have to divide the measurement of the diameter by two, and the number found represents the radius.

Radius=Diameter/2
Radius=9 inches/2
Radius=4.5 inches

Now that the radius is known, you can find the area of the circular plate by substituting the value representing the radius into the formula, A=πr^2.

A=πr^2
A=π(4.5 in)^2
A=π(20.25 in^2)
A=63.62 in^2 or 20.25π in^2

The area of the circular plate is 63.62 in^2 or 20.25 in^2 in terms of pi.