Right Angled Triangle Angle Calculator

Applies to the angles you type in and to the angleA / angleB / angleC outputs.
Angle A
36.869898
Right Triangle Calculator
Leg a
3
Leg b
4
Hypotenuse c
5
Angle B
53.130102
Angle C (right angle)
90
Angle A in degrees
36.869898 deg
Angle A in radians
0.643501 rad
Angle B in degrees
53.130102 deg
Angle B in radians
0.927295 rad
Area
6
Perimeter
12
Altitude to the hypotenuse
2.4
Hypotenuse segment next to leg a
1.8
Hypotenuse segment next to leg b
3.2
Inradius
1
Circumradius
2.5
Median to the hypotenuse
2.5
sin A (opposite / hypotenuse)
0.6
cos A (adjacent / hypotenuse)
0.8
tan A (opposite / adjacent)
0.75
Whole-number (Pythagorean) triple
Yes
Solved from
two legs (Pythagoras)
Worked out from Euclid, Elements, Book I Proposition 47 (the Pythagorean theorem) and 3 other sources.

How this is worked out

5 steps
  1. Solved from two legs (Pythagoras).
  2. Legs a = 3, b = 4; hypotenuse c = sqrt(a^2 + b^2) = 5.
  3. Angle A = arctan(a/b) = 36.86989764584402 deg, angle B = 90 - A = 53.13010235415598 deg.
  4. Area = a*b/2 = 6; perimeter = a + b + c = 12.
  5. Altitude to the hypotenuse = a*b/c = 2.4; the right angle's vertex projects onto the hypotenuse dividing it into a^2/c and b^2/c.

Results are general information, not financial, tax, legal, medical or engineering advice.