Missing Side of a Right Triangle Calculator
Created by Kaushik RabadiyaLast updated: June 14, 2024Missing side of a right triangle instantly calculates results using angle alfa, angle beta, sidea. Use the calculator above for instant answers in your browser.
Key takeaway: Find the third side of a right triangle using the missing side of a right triangle calculator. This free Missing Side of a Right Triangle Calculator is designed for students, teachers, and anyone who needs quick math answers — enter your values above to get instant results.
The missing side of a right triangle calculator will help you find the third side or any third angle for a right-angled triangle.
A triangle is right-angled if one of the three angles is 90°, i.e., any two sides are perpendicular. In this calculator, we use this property to deliver a calculator that enables you to find the missing side of a right triangle. Read on to understand how to find the missing side of a right triangle.
Missing side of a right triangle
The formula that relates the sides of the triangle to its angles is the sine law. For a triangle having three sides as , , , and the angles , , and , it is given by the equation:
But we know that one of the angles is 90°. Therefore, the sum of the other two angles is 90°. Mathematically, if ,
Using the above relation, we get:
The above relationship, along with the Pythagoras theorem, forms the core of this tool and is used to calculate the missing sides or angles for any right-angled triangle.
Using the missing side of a right triangle calculator
Use the calculator to find the missing side of a right triangle having sides 9 and 12.
- Enter the length of the first side as
9. - Insert the length of the second side as
12. - The calculator will return the third side length as
15. - We can also get the angles for the triangle as
36.87°and53.13°using the missing side of a right triangle calculator.
FAQs
How do I find the missing side of a right triangle?
To find the missing side of a triangle: Divide the length of the first side by the second side. Find the inverse tangent of the quotient to get the angle between the two sides. Divide the length of the first side by sine of the angle to obtain the third side of the triangle.
What is the third side of a triangle having sides, 3 and 4?
The third side of the triangle is 5. First, we find the angle between the two sides, i.e., arctan (3/4) = 36.87°. Then we divide the first side by the sine of angle obtained: 3/sin(36.87°) = 5.
Formula verified against Mathematical standards (ISO 80000-2) — all calculations use deterministic, standards-based formulas.
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