Sector Area Calculation

Use radius and angle to calculate the sector area

\[ sector\, area = circle\, area \times\, angular\, ratio \\[12pt] = pi \times\, Radius^2 \times {\theta(^{\circ}) \over 360} \\[12pt] = \pi \, R^2 \times {\theta(^{\circ}) \over 360} \]

Use radius, radian to calculate the sector area

\[ sector\, area = circle\, area \times\, radian\, ratio \\[12pt] = pi \times radius^2 \times {\theta_{rad} \over 2 \times pi} \\[12pt] = {radius^2 \over 2} \times \theta_{rad} \\[12pt] = {R^2 \over 2} \times \theta_{rad} \]