Scalene Triangle Calculator
Calculate area, perimeter and angles of a scalene triangle from three unequal sides.
Inputs
units
units
units
Area
31.4195sq units
Perimeter
27.0000units
Angle A
39.4006°
Angle B
54.6955°
Angle C
85.9040°
Step by step
Semi-perimeter
s = (7+9+11)/2 = 13.5
Area (Heron's)
A = √(13.5×6.50×4.50×2.50)
= 31.4195
Angle A (law of cosines)
A = arccos((9²+11²−7²)/(2×9×11))
= 39.4006°
How it works
A scalene triangle has three unequal sides. Area is computed via Heron's formula and angles via the law of cosines.
Formula
Law of Cosines
cos(A) = (b² + c² − a²) / (2bc)
- a
- Side opposite angle A
- b
- Second side
- c
- Third side
Frequently Asked Questions
What makes a triangle scalene?
All three sides (and all three angles) are different. No two sides are equal.
Can a scalene triangle be right-angled?
Yes — a right triangle can be scalene if its three sides are all different, like the classic 3-4-5 triangle.