Circle, Square and Rectangle formula
Circle
d = 2r r = d/2
C = 2πr C = πd C = 2√πA
A = πr² A = πd² / 4 A = C² / 4π
Square
Diagonal of the square formula from | |||||||
diameter | diameter | length | |||||
side | area | perimeter | circumradius | of the circumcircle | the inradius | of the incircle | of the segment l |
d = a·√2 | d = √2A | d = P / 2√2 | d = 2R | d = Dc | d = 2r√2 | d = Di√2 | d = l (2√10/5) |
Perimeter of a square formulas from | |||||||
diameter | diameter | length | |||||
side | area | diagonal | circumradius | of the circumcircle | the inradius | of the incircle | of the segment l |
P = 4a | P = 4√A | P = 2d√2 | P = 4R√2 | P = 2Dc√2 | P = 8r | P = 4Di | P = l (8√5) |
Area of a square formulas from | |||||||
diameter | diameter | length | |||||
side | perimeter | diagonal | circumradius | of the circumcircle | the inradius | of the incircle | of the segment l |
A = a² | A = P²/16 | A = d² / 2 | A = 2R² | A = Dc² / 2 | A = 4r² | A = Di² | A = l ²(16√5) |
Circumradius of a square formulas from | |||||||
diameter | diameter | length | |||||
side | perimeter | diagonal | area | of the circumcircle | the inradius | of the incircle | of the segment l |
R = a √2 / 2 | R = P / 4√2 | R = d / 2 | R = √2A / 2 | R =Dc / 2 | R = r √2 | R = Di √2 / 2 | R = l √10/5 |
inscribed circle of a square formulas from | |||||||
diameter | diameter | length | |||||
side | perimeter | diagonal | area | of the circumcircle | circumradius | of the incircle | of the segment l |
r = a / 2 | r = P / 8 | r = d / 2√2 | r = √A / 2 | r = Dc / 2√2 | r = R / √2 | r = Di / 2 | r = l / √5 |
Rectangle
Rectangle sides from | ||||
diagonal | area | perimeter | ||
and rectangle side | and rectangle side | and rectangle side | diagonal | diagonal |
a = √(d² - b²) | a = A / b | a = (P - 2b) / 2 | a = d sinα | a = d sin β / 2 |
b = √(d² - a²) | b = A / a | b = (P - 2a) / 2 | b = d cosα | b = d cos β / 2 |
Diagonal of a rectangle from | ||||
radius of the | diameter of the | |||
area | perimeter | escribed circle | escribed circle | |
rectangle sides | and rectangle side | and rectangle side | (excircle) | (excircle) |
d = √(a² + b²) | d = √(A² + a4) / a | d = √(P² - 4Pa + 8a²) / 2 | d = 2R | d = Dc |
d = √(A² + b4) / b | d = √(P² - 4Pb + 8b²) / 2 | |||
sine of the angle that adjacent | cosine of the angle that adjacent | |||
to the diagonal | to the diagonal | sine of the acute angle between | ||
and the opposite side of the angle | and the opposite side of the angle | the diagonals and the area | ||
d = a / sin α | d = c / cos α | d = √2A / sin β | ||
Perimeter of a rectangle from | ||||
radius of the | diameter of the | |||
area | diagonal | escribed circle | escribed circle | |
rectangle sides | and rectangle side | and rectangle side | (excircle) | (excircle) |
P = 2a + 2b | P = (2A + 2a²) / a | P = 2(a + √(d² - a²)) | P = 2(a + √(4R² - a²)) | P = 2(a + √(Dc² - a²)) |
P = (2A + 2b²) / b | P = 2(b + √(d² - b²)) | P = 2(b + √(4R² - b²)) | P = 2(b + √(Dc² - b²)) | |
Area of a rectangle | ||||
radius of the | diameter of the | |||
perimeter | diagonal | escribed circle | escribed circle | |
rectangle sides | and rectangle side | and rectangle side | (excircle) | (excircle) |
A = a · b | A = (Pa - 2a²) / 2 | A = a√(d² - a²) | A = a√(4R² - a²) | A = a√(Dc² - a²) |
A = (Pb - 2b²) / 2 | A = b√(d² - b²) | A = b√(4R² -b²) | A = b√(Dc² - b²) | |
sine of the acute angle between | ||||
the diagonals and the area | ||||
A = d² · sin β / 2 | ||||
An angle between the diagonal and rectangle side | ||||
sin α = a / d | cos α = b / d | α = β / 2 | ||
An angle between the rectangle diagonals | ||||
β = 2α | sin β = 2A / d² | |||
Inradius | ||||
Ri = a / 2 | ||||
Circumradius of a rectangle from | ||||
diameter of the | ||||
perimeter | area | escribed circle | ||
rectangle sides | and rectangle side | and rectangle side | diagonal | (excircle) |
R = √(a² + b² ) / 2 | R = √(P² - 4Pa + 8a²) / 4 | R = √(AS² + a4) / 2a | R = d / 2 | R = Dc / 2 |
R = √(P² - 4Pb + 8b²) / 4 | R = √(AS² + b4) / ba | |||
sine of the angle that adjacent | cosine of the angle that adjacent | |||
to the diagonal | to the diagonal | sine of the acute angle between | ||
and the opposite side of the angle | and the opposite side of the angle | the diagonals and the area | ||
R = a / 2sin α | R = b / 2cos α | R = √(2A / sin β) / 2 |