AREA OF A TRIANGLE <3 help plz

• Dec 7th 2007, 04:16 PM
Noelle
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
• Dec 7th 2007, 04:59 PM
topsquark
Quote:

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
• Dec 7th 2007, 05:03 PM
Krizalid
Quote:

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

Heron's :D

--

You can also combine Law of cosine and Law of sines to get the area, but I prefer to use Heron's Formula.
• Dec 7th 2007, 05:56 PM
Noelle
rawr
so is it supposed to be 10+3+9 = 22/2 = 11?