Summer School image
Summer School
How Is Trigonometry Used On Non-Right-Angled Triangles

How Is Trigonometry Used On Non-Right-Angled Triangles


The three primary trigonometric ratios used to solve problems in non-right-angled triangles are sine, cosine, and tangent. Students can use these ratios to solve for the length of one of the triangle's sides if they know the values of the angles and one side, essentially applying the non-right-angle triangle formula. Moreover, these ratios are interchangeable, simplifying the process of finding a solution to complex trigonometric equations.

Overview of Sine, Cosine, and Tangent Ratios

Sine (sin):

  • The sine of an angle in a right-angled triangle is the ratio of the length of the opposite side to the length of the hypotenuse (the side opposite the right angle).

  • Mathematically, for an angle θ, it is expressed as: sin()=Opposite SideHypotenuse

Cosine (cos):

  • The cosine of an angle in a right-angled triangle is the ratio of the length of the adjacent side to the length of the hypotenuse.

  • Mathematically, for an angle θ, it is expressed as: cos()=Adjacent SideHypotenuse

Tangent (tan):

  • The tangent of an angle in a right-angled triangle is the ratio of the length of the opposite side to the length of the adjacent side.

  • Mathematically, for an angle θ, it is expressed as: tan ()=Opposite  SideAdjacent Side

Angles within Non-Right-Angled Triangles

Non-right-angled triangles, where internal angles do not measure exactly 90°, can be classified as acute or obtuse. Understanding these distinctions is key in calculating the area of non-right-angle triangles.

  • An acute triangle has all internal angles less than 90°.

  • An obtuse triangle has one internal angle greater than 90°.

Calculating the area of a non-right-angle triangle also involves understanding these distinctions.

The Law of Sines

The Law of Sines is a fundamental formula for solving problems related to the area of non-right-angle triangles. It is used to find unknown angles or the length of a missing side in non-right-angled triangles.

The formula is  asin A =bsin B =csin C  where 'a, 'b,' and 'c' are the sides of the triangle, and 'A,' 'B,' and 'C' are the angles opposite of those sides, respectively. 

The Law of Cosines

The Law of Cosines is another essential tool in trigonometry and non-right triangle calculations. 

The formula is a² = b² + c² - 2bc cos(A), where A is the angle opposite the side 'a'. 

Knowing the measurements of all three sides or two sides and the angle opposite one side, we can use this formula to determine the unknown measures.

Real-world Examples of Trigonometry in Non-Right Angled Triangles

Trigonometry's application extends beyond Maths to real-world scenarios, such as surveying, architecture, satellite communication, and more, demonstrating its versatility in solving problems involving non-right angle triangle formulas.

Challenges and Considerations in Trigonometry Application

Although trigonometry is effective, students might need help applying the formulas to real problems. 

Some common issues include dealing with large or small numbers, formulae mix-ups, and difficulties interpreting word problems. However, we can overcome these challenges and become better problem solvers with practice and patience.

Tips for Problem Solving

  • Understand the Basics: Have a firm grasp of trigonometric principles and formulas.

  • Use Logical and Analytical Thinking: Apply critical thinking to assess and approach the problem.

  • Careful Reading and Application: Read the problem thoroughly and understand how to apply formulas effectively.

  • Visualize with Diagrams: Drawing the triangle can aid in better visualization and comprehension of problems involving trigonometry and non-right triangles.

  • Patience is Key: Take time to think through the problem without rushing.

Trigonometry's Versatility in Non-Right Angled Triangles

To sum up, applying trigonometry to non-right-angled triangles broadens the versatility of the subject and offers a wider range of solution possibilities. Although it might seem daunting, as with everything else, practice makes perfect. It's crucial to fully understand the principal concepts and formulas before attempting to solve complex problems and find an effective solution.

Trigonometry is vital daily, from engineering to architecture to financial planning. So, if you are interested in these areas, mastering trigonometry is critical to opening up endless possibilities in the field.

Author: MyEdSpace
Read more articles
Share this article!