what is the area of a regular, NON-right angled triangle with sides 240, 180, and 140 m?

Question

a_clan · Answer

why is it regular?

angela210793 · Answer

Use Heron's formula:A=$$\sqrt{p(p-a)(p-b)(p-c)}$$

angela210793 · Answer

where p=Perimeter/2
and a,b,c are the lengths if the sides

anonymous · Answer

Area of a triangle is $$1/2ab \sin C$$
Where a b and c are sides and A B and C are the angles opposite to the sides.

anonymous · Answer

so that is the angle inbetween the two sides, right?

angela210793 · Answer

Heron's formula works always if u have the 3 lengths....why r u mixing it with sin?

anonymous · Answer

trigonometry. never heard of heron's formula :P  but thanks guys :)

angela210793 · Answer

K..here it is http://en.wikipedia.org/wiki/Heron's_formula

anonymous · Answer

@angela triangles and trigonometry go together like butter and bread! hahaha

angela210793 · Answer

yea i know....but ..am i blind or there's no angle given...

anonymous · Answer

You use the cosine rule:
$$c ^{2} = a ^{2} + b ^{2} - 2ab \cos C$$

The reason i used this is that these fomulae are the most commonly used ones.

Heron's would be easier but is lesser known and is not usually given on formulae sheets

anonymous · Answer

@ angela: but you can find that out using the cos rule. CosA= (b^2 + c^2 - a^2)/2bc.  I am doing a past paper, so i was asking according to the instructions given.

angela210793 · Answer

I didn't know that...In Albania we use it a looooooooooot...I thought you knew it :)

anonymous · Answer

ohh. cool B)

anonymous · Answer

im gonna learn herons, it looks very useful.

angela210793 · Answer

:)lol

anonymous · Answer

@angela: wait. are you in school/college, what is the "p" in the formula?

angela210793 · Answer

finished hs
and I've written above that p=P/2( half of perimeter )

angela210793 · Answer

read the article i sent cause you'll get it

anonymous · Answer

sry, sry, didn't see that there :P

angela210793 · Answer

:)it's k