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Definition of Sine Calculator

Online sine definition calculator. Enter the opposite side and hypotenuse of a right triangle to find sin A=opposite/hypotenuse—ideal for trigonometry basics.

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sin A = opposite / hypotenuse
对边斜边A
Leg across from A
Longest side

📖 Tutorial | Sine

1. Definition
In a right triangle, sine of A is opposite over hypotenuse.
2. Formula & Notation
OppositeLeg across from A
HypotenuseLongest side
sin Aopp/hyp
3. Properties & Laws
  • sin A = opposite/hypotenuse;
  • 0
  • sin30°=1/2, 45°=√2/2, 60°=√3/2;
  • Larger angle, larger sine.
4. Steps
  1. Enter opposite and hypotenuse;
  2. Click "Find sin A";
  3. Or click "Load Example".
5. Worked Examples
Example: opposite 3, hypotenuse 5.
Solution: sin A = 0.6.
6. Common Pitfalls
Hypotenuse is longest;
Opposite, not adjacent;
Between 0 and 1.

❓ FAQ | Sine

Definition?
Opposite over hypotenuse.
Opp3 hyp5?
0.6.
Range?
0 to 1.
Special angles?
30°1/2, 45°√2/2, 60°√3/2.
Hypotenuse?
Longer than either leg.
Angle vs sine?
Larger acute angle, larger sine.