**Calculating the hypotenuse of a triangle** is very easy thanks to the Pythagorean Theorem. This theorem says that the hypotenuse is equal to the square root of the sum of the legs squared, therefore, knowing this data, we can find out the value of the hypotenuse.

With our **hypotenuse calculator online** you can directly apply the Pythagorean Theorem, but if you need to know the value of the other legs, we also have another way to apply it. calculator to solve triangles.

Article sections

## What is the hypotenuse of a triangle?

**The hypotenuse is the longest side** which has a right triangle and also corresponds to the side opposite the right angle (the 90º side).

In the image above, it would correspond to leg C of the triangle.

## How do you calculate the hypotenuse of a triangle?

As we have commented at the beginning, to calculate the hypotenuse of a triangle knowing the measure of the two legs **we have to use the Pythagorean Theorem.**

This theorem states that "the square of the hypotenuse is equal to the sum of the square of the legs", therefore, to calculate the hypotenuse we should **apply the following formula** mathematics:

c = √(a^{2} + b^{2})

By **example.**Let's imagine that we have a triangle whose legs measure 2 cm and 5 centimeters respectively. Applying the previous expression we have that its hypotenuse measures:

c=√(2^{2} + 5^{2}) = √(4 + 25) = √29 = 5.39 centimeters

As you can see, calculating this side of the triangle does not involve more difficulty than to clear the unknown in a proper way and solve the operation correctly. To do this, we **we recommend that you follow these steps**:

- Square the length of each cathetum
- Add the values obtained from the previous step
- Apply the square root to the result of step two.

If you follow this orderly methodology,** there is very little chance of getting it wrong** and if you have doubts about whether you have done it right, you can always use our calculator to compare the result you have obtained and that of our tool. If they match, congratulations!

Of course, you can use this formula for all triangles that are right angles, so it doesn't matter if it is isosceles, equilateral or any other as long as there is an angle of 90 degrees.

## Calculate legs knowing the hypotenuse

If we are asked to **Calculate the legs of the triangle knowing the hypotenuse.** and we are not given any other data, then we automatically know that it is an isosceles triangle and, therefore, it has two equal sides. This means that the formula of the Pythagorean Theorem applied to this example will be as follows:

c^{2} = a^{2} + a^{2} = 2a^{2}

The value of 'c' will be the hypotenuse and the value of 'a' will be the value of the legs that we have to calculate. Now we have to clear from the above formula the value of a:

a = c/√2

That is, if we have to** to find the value of the legs of a triangle from the hypotenuse** we will have to divide it by the square root of two.

## Calculate hypotenuse with cathetus and angle

We can also **calculate the hypotenuse of a triangle if we are given one of the legs and the angle**. Here is the formula for the two possible cases.

If we are given the angle and the opposite cathetus, we can calculate it with this formula:

h = opposite cathetus / sin(θ)

In the case that we are given the adjacent leg and the angle, the formula we will use will be this other one:

h = adjacent cathetus / cos(θ)

For example, let's find the hypotenuse of a triangle of which we know that it has an angle of 30º and its opposite leg measures 20 cm. To solve it, we use the first formula and solve:

h = opposite / sin(θ) = 20 cm / sin(30) = 20 cm x 0.5 = 10 cm

Easy, isn't it? If you have any doubt or problem regarding the calculation of the hypotenuse, leave us a comment and we will help you as soon as possible.

## Hypotenuse of a square

There is no **hypotenuse in a square**or at least that's not the right way to name it. Actually, what you are looking for is how to calculate the diagonal of a square and in the link we have just left you will find all the details to do so.

can you help me please I need to calculate the height of an equilateral triangle of 10 cm of side.

Hello Ingrid,

You can calculate it here:

https://www.calculadoraconversor.com/perimetro-triangulo-equilatero/

Just apply the formula at the end of the article, which will give you a height of 8.66 centimeters.

Greetings!

I have a doubt about the last exercise. Why at the end multiply 20 x 0.5?

Hoola Macarena,

If you notice, the formula to calculate the hypotenuse of a triangle from the opposite angle is this:

h = opposite cathetus / sin(θ)

In the statement we are told that the opposite leg is 20 centimeters and the angle is 30º. If we calculate the sine of 30º, the result is 0.5.

Therefore, we multiply 20 x 0.5.

Greetings!

If I have the hypotenuse and the adjacent leg, what is the formula to calculate the opposite leg? H= 192, A=168 B=?

I would like to calculate how much is B I try to do the inverted formula but I am missing an ingredient. Thanks for your help

Hello Elias,

To solve the exercise you are asking us to do we have to use the Pythagorean Theorem.

With the data you give us, leg B would measure 92.95 cm.

If you want to learn how we have solved the exercises, click on the link we have left you and if you have any doubts, ask us with complete confidence.

Greetings!

Hello, can you help me find the hypotenuse of a right triangle with legs 1 and 1?

Hello Juan,

Your problem is very easy to solve. We explain it to you below:

h = √(a

^{2}+ b^{2}) = √(1 + 1) = √2 = 1,41 cmSince the two legs are equal and of value 1, the value of the hypotenuse is obtained by calculating the square root of 2.

hello could you help me to find the cathetus of a scalene triangle, I have the value of the hypotenuse which is 1,52

Good morning Daniela:

It is impossible to find both legs if we only know the hypotenuse, we should know at least two pieces of information.

Greetings.

Bc=8sen42° could you tell me how to calculate it?

Calculate the hypotenuse with the following data: a height of: square root of 2 and a base of: square root of 3.

Hello, I want to know what is the length of the hypotenuse of a triangle whose legs measure 2cm and 3cm, and if the length of the legs is 3cm and 4cm?

Hello Aracelys,

In the first case the hypotenuse would be 3.61cm and in the second case it goes up to 5cm.

Remember that you have the calculator to do it yourself immediately with the values you want.