0Scared of trigonometry? You're not alone.
Most Class 10 students lose marks here, not because it's hard, but because nobody showed them the simple way. Let's fix that.
Step 1: Know your triangle
In a right-angled triangle, pick an angle θ. Then:
- Hypotenuse: the longest side (opposite the 90° angle)
- Opposite: the side facing θ
- Adjacent: the side next to θ
Step 2: Remember with SOH-CAH-TOA
- SOH: sin θ = Opposite / Hypotenuse
- CAH: cos θ = Adjacent / Hypotenuse
- TOA: tan θ = Opposite / Adjacent
Example: In a 3-4-5 triangle, if the side opposite θ is 3, the adjacent side is 4 and the hypotenuse is 5:
sin θ = 3/5, cos θ = 4/5, tan θ = 3/4
Step 3: Never forget the standard values
Write sin for 0°, 30°, 45°, 60°, 90° as: √0/2, √1/2, √2/2, √3/2, √4/2.
Simplify them and you get 0, 1/2, 1/√2, √3/2, 1.
For cos, just write the same values in reverse order.
Try it: Real-life problem
A 10 m ladder leans against a wall, making a 60° angle with the ground. How high does it reach?
Solution: Try first. :)
Your turn (practice question)
If sin θ = 5/13, find cos θ and tan θ.
Hint: find the adjacent side first using Pythagoras.
Post your answer in the messages and I'll check it.
Exam tip: Always draw the triangle and label the sides before writing any formula. This alone prevents most silly mistakes.
Want to score full marks in Trigonometry? Message me on UrbanPro to book a free demo class. I teach concepts step by step so that every student feels confident before exams.
