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    Trigonometry
    High School
    Periodic Circular & Harmonic Ratio

    Area of Triangle (SAS)

    Find a triangle's area from two sides and the angle between them

    Standard Formula
    A = ½ab·sin(C)

    Interactive Sandbox

    Live Reactive

    Adjust values in real-time and observe mathematical cause-and-effect

    a
    m
    120
    b
    m
    121
    C
    °
    1135
    Live EquationFormula Proof
    A = ½ab·sin(45) = 12.37
    h=6b=7
    Area = ½ × b × h = 21.0
    Calculated Solution
    12.37 m²

    Bounded Oscillatory Function: Sine and cosine oscillate smoothly between -1 and +1 with period 360° (2π rad).

    Variable Mechanics

    Roles, constraints & impacts

    3 Params
    a

    Side a

    Formula Parameter

    m
    ImpactDirect contribution
    ConstraintReal numbers
    b

    Side b

    Formula Parameter

    m
    ImpactDirect contribution
    ConstraintReal numbers
    C

    Included Angle

    Formula Parameter

    °
    ImpactDirect contribution
    ConstraintReal numbers

    At a Glance

    Gotchas, units & real-world use

    Essential

    Formula Nature & Mechanics

    Bounded Oscillatory Function: Sine and cosine oscillate smoothly between -1 and +1 with period 360° (2π rad).

    Common Mistakes & Traps

    • Using Degree mode when Radians are expected (or vice versa).
    • Tangent asymptotes at 90° and 270° (division by cos θ = 0 causes undefined infinity).
    • Forgetting inverse trigonometric domain limits (e.g., arcsin input must be between -1 and 1).

    Dimensional Analysis & Units

    Ratio of side lengths → Dimensionless Scalar [-1, +1]

    Real-World & Industry Application

    Audio sound wave synthesis, AC alternating current electrical waveforms, robotic arm joint kinematics, and astronomical navigation.

    📖 Beginner's guideTriangle Area From Two Sides and an Angle (SAS)Learn how to find a triangle's area from two sides and the angle between them using A = ½ab·sin(C), with an example and a free calculator.

    Worked Example: Area of Triangle (SAS)

    Given:

    • a = 5
    • b = 7
    • C = 45
    1. A = ½ab·sin(C)
    2. A = ½(5)(7)·sin(45°)
    3. A = 17.5 × 0.7071
    4. A = 12.37 square units

    Answer: 12.37

    Frequently Asked Questions

    What is the Area of Triangle (SAS) formula?

    A = ½ab·sin(C). Find a triangle's area from two sides and the angle between them.

    How do I calculate Area of Triangle (SAS)?

    Enter Side a (a), Side b (b), Included Angle (C) into the calculator. It applies A = ½ab·sin(C) and shows every step of the working.

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