What number should be added to each of the numbers 8, 21, 13 and 31 so that the resulting numbers in this order form a proportion?
What should be added to each of the numbers 1, 21, and 121 so that the resulting numbers are in continued proportion? ___
What should be added to each of the numbers 1, 21 and 121 so that the resulting numbers are in continued proportion?
What number should be added to 2, 4, 7 so that resulting numbers are in continued proportion.