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OBTUSE ANGLED TRIANGLE
A = area
A =
if S = ( a + b + c ) then,
A =
√
S(S -a) (S - b) ( S - c)
CIRCLE
A = area C = circumference
A =
π
r² = 3.1416
r²
A = = 0.7854 d²
C = 2
π
r = 6.2832r = 3.1416d
r = C ÷ 6.2832 =
√
A ÷ 3.1416 = 0.564
√
A
d = C ÷ 3.1416 =
√
A ÷ 0.7854 = 1.128
√
A
REGULAR HEXAGON
A = area
R = radius of circumscribed circle
r = radius of inscribed circle
A = 2.598S² = 2.598R² = 3.464r²
R = S = 1.155r
r = 0.866S = 0.866R
bh
2
= a² -
(
)
√
c² - a² - b²
2b
²
1
2
b
2
c
b
a
r
d
h
r
60°
R
s
π
d²
4
The construction of a regular hexagon forms six equilateral triangles,thus
the area of the hexagon can also be found by calculating the area of the
equilateral triangle and multiplying the result by six.
