area of circles and triangles and quadrilaterals

area of circles and triangles and quadrilaterals

1. area of triangle = ½ x base x vertical height = ½ a b Sin C

2. area of parallelogram = base x vertical height

3. area of trapezium = average of parallel sizes x distance between them

4. area of circle = pi x r*2

5. area of sector = angle/360 x area of circle

6. length of arc = angle/360 x circumference

7. area of segment = find area of the sector you make by joining sides of the chord to the centre. then find area of triangle (½ base x height or ½ a b sinC), and then subtract it from area of sector