; Commonly used standard (Euclidean) geometric formulas

; Triangle area:
triangle_area = base*height/2
; See file "heron.in" for Heron's formula for the area of any triangle
; given all three side lengths.

; Rectangle of length "l" and width "w":
rectangle_area = l*w
rectangle_perimeter = 2*l + 2*w

; Trapezoid of parallel sides "a" and "b", and the "distance" between them:
trapezoid_area = distance*(a + b)/2

; Circle of radius "r":
circle_area = pi*r^2
circle_perimeter = 2*pi*r

; Rectangular solid of length "l", width "w", and height "h":
brick_volume = l*w*h
brick_surface_area = 2*l*w + 2*l*h + 2*w*h

; Sphere of radius "r":
sphere_volume = 4/3*pi*r^3
sphere_surface_area = 4*pi*r^2

; Convex polygon with straight sides, sum of all interior angles formula:
sum_degrees = (sides - 2)*180
sum_radians = (sides - 2)*pi
; "sides" is the number of sides.