
Sin 60 Degrees Formula Derivation and Solved Examples
The concept of sin 60 degrees plays a key role in mathematics and is widely applicable to both real-life situations and exam scenarios. From geometry to trigonometry and physics, knowing the exact value of sin 60 degrees helps solve triangles, word problems, and even physics questions with speed and accuracy.
What Is Sin 60 Degrees?
Sin 60 degrees is a trigonometric value representing the ratio of the length of the side opposite a 60° angle to the hypotenuse in a right-angled triangle. You’ll find this value applied in topics such as trigonometric ratios, the unit circle, and geometry word problems.
Key Formula for Sin 60 Degrees
Here’s the standard formula: \( \sin 60^\circ = \frac{\sqrt{3}}{2} \) or approximately \( 0.866 \)
| Angle (Degrees) | Angle (Radians) | Sin Value (Fraction) | Sin Value (Decimal) |
|---|---|---|---|
| 60° | π/3 | √3/2 | 0.866 |
Cross-Disciplinary Usage
Sin 60 degrees is not only useful in Maths but also plays an important role in Physics, Computer Science, and logical reasoning. Students preparing for JEE, NEET, and board exams often encounter problems that use this value for solving triangles, vector decomposition, and even calculation of heights and distances. It’s also a basic building block for advanced trigonometry, as well as other standard trigonometric angles.
Step-by-Step Illustration
-
Draw an equilateral triangle with all sides = 2 units. Drop a height from one vertex to the base.
This height splits the base into 1 unit + 1 unit and creates two 30-60-90 right triangles.
-
Calculate the height using Pythagoras’ Theorem:
Let height = h.
\( h^2 + 1^2 = 2^2 \Rightarrow h^2 = 4 - 1 = 3 \Rightarrow h = \sqrt{3} \) -
In the right-angled triangle, for angle 60°:
Opposite = h = √3, Hypotenuse = 2
\( \sin 60^\circ = \dfrac{\text{Opposite}}{\text{Hypotenuse}} = \dfrac{\sqrt{3}}{2} \) - Decimal value: \( \sin 60^\circ \approx 0.866 \)
Sin 60 Degrees in Trigonometric Table
| Angle | Sin Value | Cos Value | Tan Value |
|---|---|---|---|
| 0° | 0 | 1 | 0 |
| 30° | 1/2 | √3/2 | 1/√3 |
| 45° | 1/√2 | 1/√2 | 1 |
| 60° | √3/2 | 1/2 | √3 |
| 90° | 1 | 0 | undefined |
Sin 60 Degrees in Different Forms
| Form | Sin 60° Value |
|---|---|
| Fraction/Surd | √3/2 |
| Decimal | 0.866 |
| Radian form | sin(π/3) |
| Unit circle (coordinates) | (½, 0.866) |
Applications of Sin 60 Degrees
You’ll use sin 60 degrees in lots of practical problems. For example, calculating the height of a triangle given the hypotenuse, working with trigonometric ratios, or decomposing forces at a 60° angle in physics. It’s also vital for MCQ accuracy and last-minute revision before competitive exams like JEE and CBSE boards.
Solved Example:
Find the perpendicular height of an equilateral triangle of side 4 cm.
1. Each side = 4 cm. Height splits base into 2 cm.
2. By Pythagoras’ Theorem,
\( h^2 + 2^2 = 4^2 \implies h^2 = 16 - 4 = 12 \implies h = 2\sqrt{3} \) cm
So, height = \( 2\sqrt{3} \) cm = 3.464 cm (using sin 60° value)
Speed Trick or Vedic Shortcut
Here’s a fast recall trick: The value of sin 60° is always larger than sin 30° and sin 45° but less than sin 90°. A memory hack is “increasing order for sin: 30° (½), 45° (1/√2 ≈ 0.707), 60° (√3/2 ≈ 0.866), 90° (1).” Vedic methods and quick tables are shared in Vedantu’s live coaching for rapid revision and MCQ speed.
Try These Yourself
- Derive sin 60° using a triangle with sides 2 units and a height.
- Find the value of sin 60° + cos 30°.
- If sin A = √3/2, what is the value of angle A?
- Express sin 60 degrees in terms of tan 60 degrees.
Frequent Errors and Misunderstandings
- Mixing up sin 60 degrees (√3/2) with sin 30 degrees (½).
- Confusing surd and decimal values during MCQ exams.
- Incorrect use of calculators: forgetting to switch to degree/radian mode.
- Using the trigonometric table for the wrong quadrant or angle.
Relation to Other Concepts
The idea of sin 60 degrees connects closely to sin 30 degrees, sin 90 degrees, and cos 60 degrees. In fact, sin 60° = cos 30°, and these relations help when applying complementary angle formulas or working with the trigonometric table. Mastering sin 60 also makes right triangle and unit circle concepts clear for future topics.
Classroom Tip
A quick way to remember sin 60 degrees is to think of an equilateral triangle and realize: dropping its height always forms a 30-60-90 triangle, and the exact value pops right out as √3/2. Vedantu’s teachers often share such visual and mnemonic tricks so you can learn and recall faster during online live classes.
We explored sin 60 degrees—from its definition, key formula, derivation, applications, and common mistakes. With practice and the right memory hacks, this value will become second nature for you in exams. Keep reviewing with Vedantu to boost your confidence in trigonometry and related maths topics!
Related Links for Quick Revision:
FAQs on What Is the Value of Sin 60 Degrees
1. What is the value of Sin 60 degrees?
The value of Sin 60° is √3/2 or approximately 0.866.
- This is a standard trigonometric ratio from special angles.
- It comes from a 30°–60°–90° right triangle.
- In decimal form: √3/2 ≈ 1.732/2 ≈ 0.866.
2. How do you find Sin 60 degrees using a triangle?
You can find Sin 60° = √3/2 using a 30°–60°–90° triangle.
- Take an equilateral triangle of side 2 units.
- Divide it into two right triangles.
- Opposite to 60° = √3, Hypotenuse = 2.
- So, sin 60° = Opposite/Hypotenuse = √3/2.
3. What is Sin 60 degrees in decimal form?
The decimal value of Sin 60° is approximately 0.866.
- Exact value: √3/2
- √3 ≈ 1.732
- 1.732 ÷ 2 ≈ 0.866
4. Why is Sin 60 equal to √3/2?
Sin 60° equals √3/2 because of the side ratios in a 30°–60°–90° triangle.
- Side ratios are 1 : √3 : 2.
- The side opposite 60° is √3.
- The hypotenuse is 2.
- So, sin 60° = √3/2.
5. What is the exact value of Sin 60 degrees?
The exact value of Sin 60° is √3/2.
- This is a standard trigonometric constant.
- It is commonly used in geometry and trigonometry problems.
- The decimal approximation is 0.866.
6. How is Sin 60 degrees used in trigonometry problems?
Sin 60° is used to find missing sides or angles in right triangles where one angle is 60°.
- Use the formula: sin θ = Opposite/Hypotenuse.
- If θ = 60°, substitute sin 60° = √3/2.
- Example: If hypotenuse = 10, opposite side = 10 × √3/2 = 5√3.
7. What is the difference between Sin 60° and Cos 60°?
The value of Sin 60° is √3/2 while Cos 60° is 1/2.
- Sin measures opposite/hypotenuse.
- Cos measures adjacent/hypotenuse.
- They are complementary: sin 60° = cos 30°.
8. Is Sin 60 degrees greater than Sin 45 degrees?
Yes, Sin 60° (√3/2 ≈ 0.866) is greater than Sin 45° (√2/2 ≈ 0.707).
- 0.866 > 0.707
- On the unit circle, sine increases from 0° to 90°.
- Therefore, sin 60° is larger than sin 45°.
9. What is Sin 60 degrees on the unit circle?
On the unit circle, Sin 60° is the y-coordinate of the point, which is √3/2.
- Coordinates at 60° are (1/2, √3/2).
- Sine represents the vertical (y) value.
- Thus, sin 60° = √3/2.
10. Can you give a real-life example using Sin 60 degrees?
Sin 60° can be used to calculate height or distance in real-life right triangle problems.
- Example: A ladder makes a 60° angle with the ground.
- If the ladder length is 8 m, height reached = 8 × √3/2.
- Height = 4√3 ≈ 6.93 m.





















