Tan is short for tangent. Here we tell you what tan 21 degrees is, how we came up with the answer, and how knowing tan of 21 degrees can be useful.
To calculate tan (21) degrees of a right angled triangle, we use the following equation where angle is 21:
Tan(angle) = Opposite/Adjacent
Tan 21 degrees is simply the ratio of the side opposite of the angle to the side adjacent to the angle. As long as the angle stays at 21 degrees, the ratio does not change and tan 21 degrees is a fixed number. See figure 1 for a better illustration. The answer to "What is tan 21 degrees?" is as follows:
Tan(21 deg) ≈ 0.383864035035
Now you also know that the following is true:
0.383864035035 ≈ Opposite/Adjacent
This is useful because if you know either Opposite or Adjacent length, you can enter it in the equation above and solve for the missing length.
You can also re-write the equation above to solve for Opposite and Adjacent to get the following new equations:
Opposite ≈ 0.383864035035 x Adjacent
Adjacent ≈ Opposite / 0.383864035035
Tan of the angle in the illustration above is calculated by dividing the length of the Opposite by the length of the Adjacent.
If the angle is 21, then the tan of 21 degrees will be 0.383864035035.
To find tan of another number, please enter the number below and press "Calculate Tan".
What is Tan 22 degrees?
Go here for the next angle we converted.