How to use sin cos tan to find a side

Tan θ = Opposite side/Adjacent side = BC/AB We can see clearly from the above formulas, that: Tan θ = sin θ/cos θ Now, the formulas for other trigonometry

How do you know when to use cos, sin, tan in trigonometry?

Start with: sin 39° = opposite/hypotenuse sin 39° = d/30 Swap Sides: d/30 = sin 39° Use a calculator to find sin 39°: d/30 = 0.6293 Multiply both sides by 30: d = 0.6293 x 30 d = 18.88

Finding a Side in a Right-Angled Triangle

We can use the sine rule when we're given the sizes of: two sides and one angle (which is opposite to one of these sides) one side and any two angles Example Find the size of angle R. \