Oblique Triangle

Oblique triangle equations

Triangle Three Known Values - Length and Angle Calculator

Calculate the unknown lengths and angles in a triangle. Add three known values - leave the rest of the inputs blank.

Note! - the calculator is based on the same value combinations used in the equations below. Other value combinations will not work - most triangles with three known values can be adapted to these equations. The calculator is quite simple. With strange results - check your input values.

Angle A (degrees)

Angle B (degrees)

Angle C (degrees)

Length a (m, mm, ft, in ..)

Length b (m, mm, ft, in ..)

Length c (m, mm, ft, in ..)

Area (m², mm², ft², in² .....):

(enable pop-up)

A, B and a is known, calculate

b = a sin(B) / sin(A) (1a)

C = 180^o - (A + B) (1b)

c = a sin(C) / sin(A) (1c)

A, a and b is known, calculate

sin(B) = b sin(A) / a (2a)

C = 180^o - (A + B) (2b)

c = a sin(C) / sin(A) (2c)

a, b and C is known, calculate

tan(A) = a sin(C) / (b - a cos(C)) (3a)

B= 180^o - (A + C) (3b)

c = a sin(C) / sin(A) (3c)

a, b and c is known, calculate

cos(A) = (b² + c² - a²) / (2 b c) (4a)

cos(B)= (a² + c² - b²) / (2 a c) (4b)

C = 180^o - (A + B) (4c)

a, b, c, A, B and C is known, calculate area

s = (a + b + c) / 2 (5a)

area = (s (s - a) (s- b) (s - c))^1/2 (5b)

area = b c sin(A) / 2 (5c)

area = a² sin(B) sin(C) / (2 sin(A)) (5d)

Tag Search

en: oblique triangle formulas
es: fórmulas de triángulos oblicuos
de: schräge Dreieck Formeln

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