Ratio of 21 to 81 (21:81)

Ratio of 21 to 81

A ratio of 21 to 81 can be written as 21 to 81, 21:81, or 21/81. Furthermore, 21 and 81 can be the quantity or measurement of anything, such as students, fruit, weights, heights, speed and so on.

A ratio of 21 to 81 simply means that for every 21 of something, there are 81 of something else, with a total of 102.

In the box below, you can enter a number in either box and we will calculate the other number to keep the ratio of 21 to 81. In other words, we will calculate the corresponding equivalent ratio of 21:81 for you.

To calculate the left side of the ratio, our calculator multiplies the right side by 21 and then divides the product by 81. To calculate the right side of the ratio, our calculator multiplies the left side by 81 and then divides the product by 21. Answers are rounded to two decimals if necessary.

Below is a list of equivalent ratios of 21:81 that we created using our 21:81 ratio calculator above.

7:27

14:54

21:81

28:108

35:135

42:162

49:189

56:216

63:243

70:270

77:297

84:324

We have also created a pie chart for you to put 21:81 ratio in perspective. To do so, we divided a pie into 102 pieces and then colored 21 pieces green and 81 pieces blue. The pie will look exactly the same using any equivalent ratio of 21:81.

21 to 81 pie ratio

The green part of the pie covers 20.59% and the blue part covers 79.41%. To calculate the percentages, we divided each side of the ratio by its total and then multiplied by 100, like this:

(21 / 102)×100 ≈ 20.59
(81 / 102)×100 ≈ 79.41

In fractional terms, 21/81 of the pie above is colored in green. This means that the ratio of 21 to 81 or 21:81 can also be expressed as a fraction, where the 21 to the left of the colon is the numerator and the 81 to the right of the colon is the denominator:

21:81 = 21/81

Ratio is often used when defining rectangles in width:height format. Width and height can be feet, inches, centimeters, or any other kind of length. With a ratio of 21 to 81, the width is 21 and the height is 81. Below is a picture of what a rectangle with a ratio of 21:81 looks like.

21 to 81 pie rectangle

Since the simplest form of the fraction 21/81 is 7/27, the simplest form of the ratio 21:81 is also 7:27.

Ratio Calculator
Need information about another ratio? Here you can submit another ratio for us to explain.

Ratio of 21 to 82
Go to the next ratio on our list that we have detailed information about.