Final answer:
The geometric mean of 7 and 12 is C. 2√21.
Step-by-step explanation:
The geometric mean is a measure of central tendency that calculates the average of a set of numbers using the product of their values, rather than the sum. To find the geometric mean, multiply all the values together and then take the nth root, where n is the number of values. It is commonly used in various fields, including finance and biology.
For the given case, the geometric mean of 7 and 12 can be found by taking the square root of their product.
Geometric mean = √(7 * 12)
= √84 = 2√21.
Therefore, the correct answer is option c. 2√21.