Area formula for all figures

Area formula for all figures

All figure area formulas?

The area formula of various figures
It's better to use Chinese instead of formula

Circle π R ^ 2
Ellipse π ab
Rectangle ab
Circle inscribed quadrilateral root ((S-A) (S-B) (S-C) (S-D))
S = (a + B + C + D) / 2 a B C D side length
Under the square root ((S-A) (S-B) (S-C) (S-D) - ABCD (COS θ) ^ 2) s = (a + B + C + D) / 2 a B C D side length 2 θ is the sum of diagonals
Triangle (1) absin C / 2
(2) Under the radical ((S-A) (S-B) (S-C))
s=(a+b+c)/2
(3) a^2sinBsinC/2sinA
（4）ah/2
Parallelogram ah absin θ
Trapezoidal (a + b) H / 2
Sector LR / 2 or (θ R ^ 2) / 2
Arcuate R ^ 2 (θ - sin θ)
Ring π (R ^ 2-r ^ 2)
Ring sector 1 / 2 * θ (R ^ 2-r ^ 2)
R small circle radius r large circle radius θ center angle (radian) l arc length