# Is it a Right Triangle Calculator

Table of contents

What is a right triangle and how to tell if it is a right triangle?How to figure out if it is a right triangle - Calculator guideOther related calculatorsFAQsThis **is it a right triangle calculator** will help you determine whether or not a triangle qualifies to be a right triangle. This tool will be your companion when you just want to make sure you have a right triangle. In this right triangle calculator, you will learn:

**What a right triangle is**; and**How to figure out if a triangle is a right triangle**using our calculator.

You're on the right track, so keep on reading.

## What is a right triangle and how to tell if it is a right triangle?

A right triangle is a triangle with one of its interior angles equal to 90°, hence the name. Since a triangle has a total of 180° for its interior angles, if one of its angles is 90°, that means its two remaining interior angles have a total of 90°, too. So to check if a triangle is right, its two remaining angles need to be complementary and acute (since every complementary angle is acute). In equation form, we express that as:

where:

- $\alpha$ and $\beta$ - Remaining angles of a right triangle that turn out to be complementary.

Aside from the relationship of the interior angles of a right triangle, its sides should also follow the Pythagorean theorem. That means that a right triangle has to have a hypotenuse, which we can denote as $c$, which has a length equal to:

where:

- $a$ and $b$ - Sides of the triangle forming a right angle.

Lastly, we can observe the following trigonometric functions when dealing with right triangles:

**For angle $\alpha$:**

**For angle $\beta$:**

Note that:

- $a$ - Length of side opposite angle $\alpha$;
- $b$ - Length of side opposite angle $\beta$; and
- $c$ - Length of the hypotenuse, or the side opposite the 90° angle.

If a triangle fails to meet even one of these conditions, then that triangle is not a right triangle.

## How to figure out if it is a right triangle - Calculator guide

You can check your triangle in three different ways depending on the known parameters of the triangle you have. To use our right triangle calculator:

- Choose in the
**Given**selection your known set of parameters whether you know the`3 sides`

,`angles α and β`

, or`2 sides and 1 angle`

. - Skip this step if you choose any of the first two options. If you chose
`2 sides and 1 angle`

,**select among the options**which sides and angle you know. **Enter your known measurements**depending on your selections.

After entering your last known parameter, our calculator will then display a message if your triangle is a right triangle or not.

### Is it possible to draw a right isosceles triangle?

**Yes, it is possible**. To draw a right isosceles triangle, make sure the sides forming the right angle have equal lengths. Then connect their ends to draw a hypotenuse to form a right isosceles triangle. Drawing a diagonal inside a square will also let you draw right isosceles triangles.

### How do I tell if it is a right triangle?

To determine a right triangle, check if:

- One of its interior angles is equal to 90°.
- The sum of two of its angles is equal to 90°.
- Its longest side, say
`c`

, is equal to the square root of the sum of the square of the two shorter sides, say`a`

and`b`

. In equation form:`c = √(a² + b²)`

. - It can meet any of these conditions:

- sin(α) = a/c
- cos(α) = b/c
- tan(α) = a/b

where `a`

is the **side opposite angle α**, `b`

is the **side adjacent to angle α**, and `c`

is the **hypotenuse**.