Wednesday, May 26, 2010

Heron's Formula:

Let us learn about Hero's Formula and understand this concept better:

In geometry, Heron's (or Hero's) formula, named after Hero of Alexandria, states that the area A of a triangle whose sides have lengths a, b, and c is
A = \sqrt{s(s-a)(s-b)(s-c)}
where s is the semiperimeter of the triangle:
s=\frac{a+b+c}{2}.
Heron's formula can also be written as:
A={\ \sqrt{(a+b+c)(a+b-c)(b+c-a)(c+a-b)\ \over 16}\,}
A={\ \sqrt{2(a^2 b^2+a^2c^2+b^2c^2)-(a^4+b^4+c^4)\ \over 16}\,}

A=\frac{1}{4}\sqrt{(a^2 + b^2 + c^2)^2 - 2(a^4 + b^4 + c^4)}.
Let us now look at one example of Heron's Formula:

Heron formula reduce the form on left to (ch)2, or (cb)2 − (cd)2 from 4A 2 = 4s(s − a)(s − b)(s − c). On the right side using b 2 − d 2 = h 2 by the Pythagorean theorem.We get the form like,
(s(s − a) + (s − b)(s − c))2 − (s(s − a) − (s − b)(s − c))2
Using this form (p + q) 2 − (p − q) 2 = 4pq.
cb = s(s-a) + (s-b)(s-c) and cd = s(s-a) - (s-b) (s-c).
Hope you like the above example of Heron's Formula.
Please leave your comments, if you have any doubts.

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