What is Tan 20 degrees? Tan is short for tangent. Here we tell you what tan 20 degrees is, how we came up with the answer, and how knowing tan of 20 degrees can be useful.

To calculate tan (20) degrees of a right angled triangle, we use the following equation where angle is 20:

Tan 20 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 20 degrees, the ratio does not change and tan 20 degrees is a fixed number. See figure 1 for a better illustration. The answer to "What is tan 20 degrees?" is as follows:

Tan(20 deg) ≈ 0.363970234266

Now you also know that the following is true:

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:

Figure 1 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 20, then the tan of 20 degrees will be 0.363970234266.

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What is Tan 21 degrees?
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