Right Triangle Trigonometry Calculator

Calculate all properties of right triangles using trigonometric functions and relationships

Triangle Properties

Sides

Angles

90°

Other Properties

0

Example Calculation

Given: Hypotenuse c = 5, Angle A = 38°

Step 1: Calculate angle B = 90° - 38° = 52°

Step 2: Calculate opposite side: a = c × sin(A) = 5 × sin(38°) = 5 × 0.6157 = 3.078

Step 3: Calculate adjacent side: b = c × cos(A) = 5 × cos(38°) = 5 × 0.7880 = 3.940

Step 4: Calculate area: Area = (a × b)/2 = (3.078 × 3.940)/2 = 6.063

Trigonometric Functions

Sine (sin)

sin(A) = opposite/hypotenuse

Ratio of opposite side to hypotenuse

Cosine (cos)

cos(A) = adjacent/hypotenuse

Ratio of adjacent side to hypotenuse

Tangent (tan)

tan(A) = opposite/adjacent

Ratio of opposite to adjacent side

Quick Tips

In a right triangle, one angle is always 90°

The sum of all angles equals 180°

Pythagorean theorem: a² + b² = c²

SOH-CAH-TOA helps remember trig ratios

Any two values can solve the triangle

Understanding Right Triangle Trigonometry

What is Right Triangle Trigonometry?

Right triangle trigonometry relates the angles of a right triangle to the lengths of its sides. The three primary trigonometric functions (sine, cosine, and tangent) provide the foundation for solving any right triangle when given at least two pieces of information.

Key Relationships

  • Pythagorean Theorem: a² + b² = c²
  • Complementary Angles: A + B = 90°
  • Area Formula: Area = (a × b)/2
  • Co-function Identities: sin(A) = cos(B)

Solving Methods

Given Two Sides

Use Pythagorean theorem to find the third side, then trigonometric ratios for angles.

Given One Angle and One Side

Use trigonometric functions and their inverses to find remaining sides and angles.

Given Area and One Side

Use area formula A = ½ab to find the other leg, then proceed normally.

SOH-CAH-TOA Memory Device

SOH
Sine = Opposite/Hypotenuse
CAH
Cosine = Adjacent/Hypotenuse
TOA
Tangent = Opposite/Adjacent