Question

All formulas of chapter 12

Answer 1

Answer:

Step-by-step explanation:

Circumference (perimeter) of a circle = πd or 2πr

Area of a circle = πr²

Area of a semicircle = $\frac{1}{2}$ πr²

Area of quadrant = $\frac{1}{2}$ πr²

Perimeter of a semicircle or protractor = πr + 2r

Area of the ring Formulas :

Area of the ring or an annulus = πR² – πr²

= π(R² – r²) 15θ/360° = πrθ/180°

Area of sector formula:

Area of sector = πr²θ/360°

            or

      $\frac{1}{2}$ ( r × l )

Perimeter of sector = Length of arc + 2r

                               = πrθ/180° + 2r