Right triangle calculator
Two legs determine everything else about a right triangle.
Hypotenuse
5m
- Angle opposite a
- 36.869 90 degrees
- Angle opposite b
- 53.130 10 degrees
- Area
- 6
- Perimeter
- 12
- Altitude to the hypotenuse
- 2.4
- Inradius
- 1
- Circumradius
- 2.5
Show the working
- Leg a = 3
- Leg b = 4
- Hypotenuse = hypot(3, 4) = 5
- Angle opposite a = 5 > 0 ? deg(asin(clamp(3/5, -1, 1))) : 0 = 36.8699
- Angle opposite b = 90 - 36.8699 = 53.1301
- Area = 3*4/2 = 6
- Perimeter = 3 + 4 + 5 = 12
- Inradius = (3 + 4 - 5)/2 = 1
- Circumradius = 5/2 = 2.5
- Altitude to the hypotenuse = 5 > 0 ? 3*4/5 : 0 = 2.4
Values are shown to six significant figures here; the arithmetic itself runs on exact fractions and is only rounded where a number is printed.
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The formula
- c = sqrt(a^2 + b^2)
- inradius = (a + b - c)/2, circumradius = c/2
- altitude to the hypotenuse = ab/c
The circumcentre of a right triangle sits exactly on the midpoint of the hypotenuse.