How we worked it out
Updated as you change the numbers.
- Angles from the law of cosines: cos A = (b² + c² − a²) ÷ 2bc.
- Area by Heron’s formula: √(s(s − a)(s − b)(s − c)), where s is half the perimeter.
Method and assumptions
The law of cosines and the law of sines relate a triangle’s sides and angles; any three parts that include at least one side fix the triangle. Two sides with an angle not between them (SSA) can have two solutions and is left out to avoid ambiguity.
Questions
What are the angles of a 5-6-7 triangle?
About 44.42°, 57.12° and 78.46°. Its area is 14.70 square units.
Sources
Method and figures checked on . Every worked answer on this page is covered by an automated test. Found a mistake? Tell us.