The square root of 25, written as 25, equals 5. That is, when the number 5 is squared (multiplied by itself), it produces the number 25. The symbol '\J is called a radical sign. Finding the square root of a number is the most common application of roots. The collections of numbers whose square roots are whole numbers are called perfect squares. The first ten perfect squares are: 1, 4, 9, 16, 25, 36, 49, 64, 81, and 100. The square root of each of these numbers is 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10, respectively.

To find the square root of a number that is not a perfect square, use either a calculator or the estimation method. A longhand method does exist for finding square roots, but with the advent of calculators and because of its lengthy explanation, it is no longer included in this handbook. The estimation method uses the knowledge of perfect squares to approximate the square root of a number.

answer. The square root of 31 is actually 5.568.

The cube root of 125, written as 3 125, equals 5. That is, when the number 5 is cubed (5 multiplied by itself then multiplying the product (25) by 5 again), it produces the number 125. It is common to confuse the “cube” of a number with the “cube root” of a number.

Another way to write a root is to use a fraction as the power (or exponent) instead of the radical sign. The square root of a number is written with a 1⁄2 as the exponent instead of a radical sign. The cube root of a number is written with an exponent of 1⁄3 and the fourth root with an exponent of 1⁄4 and so on.

The Functions of Numbers chart found in Figure 3-10 is included in this chapter for convenience in making computations. Each column in the chart is listed below, with new concepts explained.

Circumference is the linear measurement of the distance around a circle. The circumference is calculated by multiplying the diameter of the circle

the number of square units of measurement contained in the circle with a diameter of N. The area of a circle