Solve missing triangle legs with smart input modes. Review angles, area, and perimeter. Export clean results for homework, revision, and reports.
1) Pythagorean relation: c² = a² + b²
Missing leg: b = √(c² − a²)
2) Trigonometric ratios:
sin(θ) = opposite / hypotenuse
cos(θ) = adjacent / hypotenuse
tan(θ) = opposite / adjacent
3) Area of a right triangle:
Area = (1/2) × leg₁ × leg₂
4) Extra measures:
Perimeter = a + b + c
Altitude to hypotenuse = (a × b) / c
Inradius = (a + b − c) / 2
| Case | Known Values | Calculated Missing Leg | Hypotenuse | Area |
|---|---|---|---|---|
| Case 1 | Known leg = 3, Hypotenuse = 5 | 4 | 5 | 6 |
| Case 2 | Known leg = 6, Angle = 30°, adjacent | 3.4641 | 6.9282 | 10.3923 |
| Case 3 | Hypotenuse = 10, Angle = 40° | 6.4279 | 10 | 24.6202 |
| Case 4 | Area = 24, Known leg = 6 | 8 | 10 | 24 |
It finds a missing leg of a right triangle and also reports hypotenuse, acute angles, area, perimeter, altitude, inradius, and circumradius.
No. This page is built for right triangles only. One angle must be exactly 90 degrees for the formulas and extra measures here.
Pick the mode that matches your known values. Use leg and hypotenuse, leg and angle, hypotenuse and angle, or area and leg.
The entered angle is one acute angle of a right triangle. Acute angles must be greater than 0° and less than 90°.
In every right triangle, the hypotenuse is opposite the right angle. It is always longer than either leg.
Yes. Decimal values are accepted for lengths, angles, and area. You can also choose output precision from zero to eight places.
They are the two perpendicular sides of the right triangle. Leg A is treated as the side opposite Angle A in results.
CSV creates a spreadsheet-friendly file. PDF saves a neat report you can share, print, or attach to assignments.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.