Missing Angle Right Triangle in Degrees Calculator

A right triangle has one 90-degree angle and two other angles that add up to 90 degrees. This calculator helps you find the missing angle when you know one of the other angles.

How to Use This Calculator

To find the missing angle in a right triangle:

Enter the known angle in the input field (must be between 0 and 90 degrees).
Click the "Calculate" button.
The calculator will display the missing angle.

The calculator will automatically validate your input to ensure it's within the valid range for a right triangle angle.

The Formula Explained

In a right triangle, the sum of all three angles is always 180 degrees. Since one angle is always 90 degrees, the other two angles must add up to 90 degrees.

Missing Angle = 90° - Known Angle

This simple formula is all you need to find the missing angle in a right triangle.

Worked Examples

Example 1

If one angle in a right triangle is 30 degrees, what is the other non-right angle?

Missing Angle = 90° - 30° = 60°

The other angle is 60 degrees.

Example 2

If one angle in a right triangle is 45 degrees, what is the other non-right angle?

Missing Angle = 90° - 45° = 45°

The other angle is also 45 degrees, making this an isosceles right triangle.

Frequently Asked Questions

What is a right triangle?

A right triangle is a triangle with one angle exactly equal to 90 degrees. The side opposite the right angle is called the hypotenuse, and the other two sides are called legs.

How do I know if I have a right triangle?

You can check if a triangle is right-angled by using the Pythagorean theorem (a² + b² = c²) where c is the longest side. If this equation holds true, the triangle is right-angled.

Can a right triangle have angles other than 90, 45, and 45?

Yes, a right triangle can have any two angles that add up to 90 degrees, such as 30 and 60 degrees, or 20 and 70 degrees.