30-60-90 Triangle Calculator

Enter one side of a 30-60-90 triangle and the calculator will return the exact side ratios, area, and perimeter.

Last updated: June 2026 | By Patchworkr Team

Short Leg

Math check: short : long : hypotenuse = 1 : sqrt(3) : 2

Result

Enter a positive side length to complete the triangle.

Ratios

short : long : hypotenuse = 1 : sqrt(3) : 2

If the short leg is 5, the long leg is 5 sqrt(3) = 8.660254 and the hypotenuse is 10.

The area is 5 x 8.660254 / 2 = 21.650635 and the perimeter is about 23.660254.

This calculator uses the exact special-triangle ratios directly, so it does not depend on approximate angle measurements.

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