c = circumference = 2πr or 22/7d
Areas Circle = πr² or 0.7854 d²
Square, rectangle, rhombus or rhomboid = bh
Triangle = .5 bh
Trapezoid = .5 two parallel sides x h
Side of square of area equal to circle = 0.8862 d
Diameter of circle equal in area to square = 1.1284 side of square
Parabola = .66 bh
Ellipse = 0.7854 d1 d2
Area of any figure of four or more unequal sides is found by dividing it into triangles, finding areas of each and adding together.
Surface Area Cube = 6b²
Sphere = πd²
Lateral surface area of regular figure = .5 cbh (slant height)
Cylinder (Lateral surface area) = πdh
Cylinder (Total surface area) = πdh + 2πr2
Cone (Total surface area) = ab + c of base x .5h (slant height)
Volume Cube = b³
Sphere = 0.5236 d³
Pyramid = .33 abh
Cone = .33 abh
Cylinder = πr²h
Table of polygons S = side of polygon.
R = Radius of circumscribed circle.
r = Radius of inscribed circle.
A = Angle formed by the intersection of the sides.
Name No of sides Angle
Trigon 3 60°
Pentagon 5 108°
Hexagon 6 120°
Octagon 8 135°
Decagon 10 144°
Area of any regular polygon = Radius of inscribed circle x 1/2 number of sides x length of one side.
Right Angle Triangles Enter any two values on the illustration for live calculations.
Find Given Solution
A a, b tan A = a / b
a, c sin A = a /c
b, c cos A = b / c
B a, b tan B = b / a
a, c cos B = a / c
b, c sin B = b / c
a A, b b tan A
A, c c sin A
b, c √ c² - b²
b A, a a / tan A
A, c c / cos A
a, c √ c² - a²
c A, a a / sin A
A, b b / cos A
a, b √ a² + b²
Area a, b ab / ²
Draw a line ab 3x long. At point a scribe an arc 4x long. At point b scribe an arc 5x long to intersect a c. Join ac and b, ac and ab are at 900.