To find the missing number that completes the ratio equivalent to 7:2 _: 6, we can use cross-multiplication.
The ratio 7:2 is equivalent to 7/2, and the ratio _:6 is equivalent to x/6, where x represents the missing number.
We can set up the proportion:
7/2 = x/6
To solve for x, we can cross-multiply:
7 * 6 = 2 * x
42 = 2x
Dividing both sides by 2, we get:
x = 42 / 2
x = 21
Therefore, the missing number that completes the ratio is 21.