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AREAS RELATED TO CIRCLES “>, , , , , , Sector of a circle oe oe, Area of combination, , of plane figures, , , , , , , , , , Major sector, , e.g. —— 2 units 4}, , Area = 1R*, , Generally sector, , implies minor sector ee, , Pp Some Important Formulas :, , 1. Heron's formula : Area of a triangle = /s(s~a)(s—b)(s—c), Where s = Semi-perimeter and a, b, c are the sides of, the triangle., , , , 1, 2. Area of a triangle = 3” base * altitude, , B, , 3. Area of an equilateral triangle aT a., , 4. Area of a rectangle = Length x breadth, , 6. Area of a square of side ‘a’ = a’., , 7. Length of diagonal of a square of a side ‘a’ =v2a,, 8. Area of a parallelogram = Base x Height, , , , 9. Area of a rhombus = Hud,, , j Where d, and d, are the lengths of its diagonals. 7, , , , e.g. — 10 units —p,, i, , , , 1. If two circles touch each other externally, then the, distance between their centres is equal to sum of, their radii., , 2. If two circles touch each other internally, then the, distance between their centres is equal to difference, of their radii., , 3. The distance moved by a rotating wheel in one revolution, is equal to the circumference of the wheel., , IV rr), , III, , , , , , , , Gi., , , , NCERT / X / Area related to circle