Pythagoras’ Theorem & Trigonometry
Pythagoras' theorem
![Rendered by QuickLaTeX.com a^2+b^2=c^2](https://teach.sg/wp-content/ql-cache/quicklatex.com-b2b6cba1ef8a8a24eab094a1b8712498_l3.png)
Trigonometric ratios
![Rendered by QuickLaTeX.com \tan\theta=\frac{\text{opposite}}{\text{adjacent}}](https://teach.sg/wp-content/ql-cache/quicklatex.com-92a4543beb256e1e5346f0757b8dbd16_l3.png)
![Rendered by QuickLaTeX.com \cos\theta=\frac{\text{adjacent}}{\text{hypotenuse}}](https://teach.sg/wp-content/ql-cache/quicklatex.com-79fe31c8c056d5052fa42d47569443a1_l3.png)
![Rendered by QuickLaTeX.com \sin\theta=\frac{\text{opposite}}{\text{hypotenuse}}](https://teach.sg/wp-content/ql-cache/quicklatex.com-a34652c3534cb089dd9e49c4cc200e91_l3.png)
TOA CAH SOH is applicable for only right-angled triangles
Obtuse angles
![Rendered by QuickLaTeX.com \sin(180^\circ-\theta)=\sin\theta](https://teach.sg/wp-content/ql-cache/quicklatex.com-ab616a97bee11165e619244bf3bd9c8c_l3.png)
![Rendered by QuickLaTeX.com \cos(180^\circ-\theta)=-\cos\theta](https://teach.sg/wp-content/ql-cache/quicklatex.com-b28c1ea2385b2e23751be328a16b6003_l3.png)
Sine rule
![Rendered by QuickLaTeX.com \dfrac{a}{\sin A}=\dfrac{b}{\sin B}](https://teach.sg/wp-content/ql-cache/quicklatex.com-81773f7330a5ba49d0126e1c9586ed2d_l3.png)
Cosine rule
![Rendered by QuickLaTeX.com c^2=a^2+b^2-2 ab \cos C](https://teach.sg/wp-content/ql-cache/quicklatex.com-cea5b223b051b45db6f5d44b13bcd96c_l3.png)
Area of triangle
![Rendered by QuickLaTeX.com \text{Area of triangle}=\frac{1}{2}ab \sin C](https://teach.sg/wp-content/ql-cache/quicklatex.com-e5fdc487683f6dca77aa3b03dc01e438_l3.png)
Bearings
A bearing is a 3-digit positive number with units of degree to show direction clockwise from the north direction.