We cannot take half of 9 people. The even numbers, then, are the numbers divisible by 2: 2, 4, 6, 8, and so on. The odd numbers are 1, 3, 5, 7, and so on. If you do not know half of some even number, you can find it by decomposing it mentally into two even numbers whose half you do know.
To draw a shape, line or angle accurately using a compass and straightedge (ruler). Sometimes you are also allowed to use a protractor and triangle.
Lesson Summary. To review, the geometric mean is the nth root when you multiply n numbers together. It is used to calculate the average rate of growth when the growth is determined by multiplication as in the case of annual percentage growth of a bank account. The formula for geometric mean is found from its definition. You first multiply your numbers together and then you take the nth root where n is the number of numbers you multiplied together.