Angles, Triangles & Polygons

🦉 Names of Angles

Acute angle $(<90^\circ)$

Right angle $(90^\circ)$

Obtuse angle $(90^\circ<\theta<180^\circ)$

Reflex angle $(>180^\circ)$

🦉 Types of Angles

1. $\angle$ on a straight line

2. $\angle$ at a point

3. Vertically opposite $\angle$

4. Alternate $\angle$

5. Corresponding $\angle$

6. Interior $\angle$

🦉 Types of Polygons

\begin{array}{|c|c|} \hline \textbf{No. of sides}& \textbf{Polygons} \\\hline \text{3} & \text{triangle} \\\hline \text{4} & \text{quadrilateral} \\\hline \text{5} & \textbf{pent}\text{agon} \\\hline \text{6} & \textbf{hex}\text{agon} \\\hline \text{7} & \textbf{hept}\text{agon} \\\hline \text{8} & \textbf{oct}\text{agon} \\\hline \text{9} & \textbf{non}\text{agon} \\\hline \text{10} & \textbf{dec}\text{agon} \\\hline \end{array}

🦉 Sum of Interior & Exterior Angles

\text{Sum of interior angles} =(n-2)\times180^\circ

\text{Sum of exterior angles} =360^\circ