This document contains formulas for calculating values related to common plane figures including areas, circumferences, and other geometric properties. It lists formulas for calculating the area of circles, rectangles, regular polygons, triangles, sectors, squares, parallelograms, trapezoids, and triangles. It also provides formulas for calculating the altitude and median of a triangle, the radius of a circumscribed circle, the circumference of a circle, and the Pythagorean theorem for right triangles. Notation is provided for variables used in the formulas such as A for area, r for radius, and π for 3.1416.

1. TABLE OF FORMULAS FOR PLANE FIGURES
Notation
A = area.
a,b,c = sides of triangle.
b = lower base.
b' = upper base.
C = circumference of circle.
D = diameter of circle.
h = altitude.
P = perimeter.
7T = 3.1416.
q, t = segments of side c, of tri
angle adjacent to sides b
and a, respectively.
R = apothem of regular poly
gon.
r = radius of circle.
s = §(a + 6 + c).
FORMULAS
Areas
Circle, A = irr2= = ! r Rectangle, A =
2TL-
Regular
bh.
Equilateral polygon, A = WP-
triangle, A =
^
Sector, A =
Square, A =
ir (arc).
b
Parallelogram, A = bh. Trapezoid, A = ih(b + b').
_ abc
4r
Triangle, A = bh = Vs(. s
—
a)(s
—
b)(s
—
c)
Line Values
o
Altitude of triangle on side a, h = - Vs(s —
a)(s
a
- b)(s
- c).
Median of triangle on side a, q = |V2(6!! + c2)
-- a2.
dbc
Radius of circumscribed circle, T ~
4 Vs(s
—
o)(s -b)(s-cY
Circumference of circle, C = 2rr = ttD.
Right triangle, tf + b2 = c2 (Pythagorean
Theorem).
Generatedon2015-04-1722:02GMT/http://hdl.handle.net/2027/mdp.39015064340733
PublicDomain,Google-digitized/http://www.hathitrust.org/access_use#pd-google