The **Functions of Numbers chart** [Figure 1-10] is included in this chapter for convenience in making computations. Each column in the chart is listed below, with new concepts explained.

- Number, (N)
- N squared, (N2)
- N cubed, (N3)
- Square root of N, (√N)
- Cube root of N, ( 3√N)
- Circumference of a circle with diameter = N. Circumference is the linear measurement of the distance around a circle. The circumference is calculated by multiplying the diameter of the circle by 3.1416 (3.1416 is the number referred to as pi, which has the symbol π). If the diameter of a circle is 10 inches, then the circumference would be 31.416 inches because 10 × 3.1416 = 31.4160.
- Area of a circle with diameter = N. Area of a circle is the number of square units of measurement contained in the circle with a diameter of N. The area of a circle equals π multiplied by the radius squared. This is calculated by the formula: A = π × r2. Remember that the radius is equal to one-half of the diameter. Example: A cockpit instrument gauge has a round face that is 3 inches in diameter. What is the area of the face of the gauge? From Figure 1-10 for N = 3, the answer is 7.0686 square inches. This is calculated by: If the diameter of the gauge is 3 inches, then the radius = D⁄2 = 3⁄2 = 1.5 inches. Area = π × r2 = 3.1416 × 1.52 = 3.1416 × 2.25 = 7.0686 square inches.

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