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Finding Angles Have Become Easier With Trigonometry Formulas

Trigonometry Formulas: the name implies trigonometry is studying triangles. The trigonometry theory encompasses the use of various trigonometry identities, laws, and formulas.

Trigonometric identities are utilised in various fields of work, like stringed musical instruments, engineering fields, and other scientific specialisations.

So take a look at the definition of trigonometry before understanding the concept of finding angles.

What is Trigonometry?

In trigonometry, students are required to understand the ratios of sides of a right triangle. This can be used to determine the angle measurement. The most fundamental trigonometric terms comprise cosine and sin. Every trigonometric formula requires students to know the relationships among cosine, secant, sine, tangent, cotangent, and cosecant.

Through studying trigonometry formulas, students will also encounter the subject of Pythagorean identities such as product identities, radians and negative angles (even-odd identities), triple angle formulas, double angle formulas, and more. 

Below, we’ll examine all trigonometric equations, including the signs of ratios in different quadrants involving the cofunction identity (shifting angles), sum & difference identities, half-angle identities, double angle identities, and other trigonometric identities. 

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The Formula for Finding Angles

Before we learn the formulas to find angles, let us rectify the situations where we may have to use these formulas. There are various formulas for finding angles according to the available data

Let’s make finding angles easy by learning the formulas step by step here.

  • Finding the missing angle in any polygon: Use the interior angles formula’s sum.
  • Finding the missing angle in any right-angled triangle: Use trigonometric ratios.
  • Finding the missing angles in any non-right-angled triangle: Use the law of sines and cosines.

Trigonometry Formulas

There are a total of 6 fundamental trigonometric ratios that we use in all formulas of trigonometry. We also call them trigonometric functions and generally use all trigonometry formulas. These six essential trigonometric functions are as follows:

  • Sine
  • Cosine
  • Secant
  • Cosecant
  • Tangent
  • Cotangent

The trigonometric identities and functions are derived by utilising the right-angled triangle. When the base side and height of the right triangle are identified, we can find out the secant, cosecant, cotangent, sine, cosine, and tangent values using trigonometric formulas. These are:

Reciprocal Identities

Cosecant, cotangent, and secant, are the basic trigonometric ratios’ reciprocals of cosine, sine, and tangent.  All of these basic identities are also derived from the right-angled triangle. These reciprocal trigonometric identities are derived by using the trigonometric functions. They’re used frequently to simplify trigonometric problems and save time.

Pythagorean Identities

Periodic Identities

Periodicity identities or formulas are used to shift the angles by π, π2, and2π.

These periodicity identities are also called co-function identities. Each trigonometric identity is cyclic, meaning that they repeat themselves after a period. This period differs for numerous trigonometric identities.

Co-function Identities (in Degrees)

The co-function identities offer the interrelationship between various trigonometric functions. The co-function (periodic identities) are illustrated in the degrees here:

Trigonometry Table of all Angles (0 degree – 360 degrees)

Here there are a few special angles offered with the trigonometric numbers. To calculate the trigonometric numbers at numerous angles simple, reference angles are used. These are taken from the primary trigonometric functions. 

Further, we can conveniently derive degrees in 0, 30, 45, 60, 90, 180, 270, and 360 degrees. The trigonometric table shown below defines each value of trigonometric ratios in an easily understandable way.

Vital Angles of Trigonometry

0°, 30°, 45°, 60°, and 90° are the special angles used in trigonometry

These are the basic angles that we use while computing trigonometric problems. Hence, we suggest students memorise all values of trigonometric ratios (tangent, sine, and cosine) for these angles to ensure quick calculations.

Positive/Negative Angles

You know what, the angles could be positive/negative. If the angle forms in a counterclockwise direction from the start point in an x-y plane, it’s a positive angle. In contrast, if a clockwise angle is formed from the start point, we call it a negative angle.

Angles More Than 360°

Completing a full cycle in an x-y plane means a full circle is constructed if we begin the cycle from 0 degrees and end at 360 degrees. One full cycle resembles a unit circle as well. After that, if we continue, then the angles reach over the limit of 360°. 

Now beyond 360° at every single quadrant, you’ll get angles, like 450°, 540°, 630°, 720°, and further. At 720 degrees, two cycles are completed. Concerning radians, we measure it as 4π. Similarly, the radians value at each cycle increases as n x 2π. Here’s the table for explaining it:

Number of CyclesAngle (n x 360°)​Radians (n x 2π)

Supplementary angles ( = sum is π)

  • Cos (π – α ) = – cos α
  • Sin ( π – α ) = sin α
  • Cot (π – α) = – cot α
  • Tan (π – α ) = – tan α

Anti-supplementary Angles (= difference is π)

  • Cos (π + α ) = – cos α
  • Sin ( π + α ) = – sin α
  • Cot (π α ) = cot α
  • Tan (π α ) = tan α

Opposite Angles ( = sum is 2π)

  • Cos (2π – α ) = cos α
  • Sin ( 2π – α ) = – sin α
  • Cot (2π – α ) = – cot α
  • Tan (2π – α ) = -tan α

Complementary Angles (= sum is π/2)

  • Cos (π/2 – α ) = sin α
  • Sin ( π/2 – α ) = cos α
  • Cot (π/2 – α ) = tan α
  • Tan (π/2 – α ) = cot α

How Can Class 10-12 Buddies Remember Trigonometry Formulas?

We’ve got numerous formulas in the higher classes that somewhat prove to be difficult to remember. No worries, here are a few steps that will help you to remember them:

  1. Get familiar with all mathematical symbols.
  2. Understand the structure of the formulas and try to remember how they are derived.
  3. Practice these formulas every day. 
  4. Lastly, use flashcards of the formulas, and revise.
  5. Finally, test yourself before exams.


Now we’ve covered all the Trigonometry formulas in our article. We hope it helps. If you think you’ve got any suggestions, just let us know.

We wish you rock your exams, but before that, keep this thing in mind, education demands dedication, and if you’ve indeed got it, success is all yours.

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