# Math Help - AREA OF A TRIANGLE <3 help plz

1. ## AREA OF A TRIANGLE <3 help plz

find the area of traingle ABC if a = 10cm ,b = 3cm and c= 9cm

and i have my final exam tomorrow... so if u want to help me tonight for a while private message me we can work on msn together! yayyy ^_^ lolll

2. Originally Posted by Noelle
find the area of traingle ABC if a = 10cm ,b = 3cm and c= 9cm

and i have my final exam tomorrow... so if u want to help me tonight for a while private message me we can work on msn together! yayyy ^_^ lolll
Hero's (Heron's?) formula says that the area of a triangle is
$A = \sqrt{s(s - a)(s - b)(s - c)}$
where
$s = \frac{a + b + c}{2}$
is called the semi-perimeter.

-Dan

3. Originally Posted by topsquark
Hero's (Heron's?)
Heron's

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You can also combine Law of cosine and Law of sines to get the area, but I prefer to use Heron's Formula.

4. ## rawr

so is it supposed to be 10+3+9 = 22/2 = 11?