Volume of a triangle.

atpbx · 10 Jun 2006 at 19:21

I'm not very good with maths, how do i work out the volume of a triangle?

The dimensions are 11x20x19 (its not exact its for an area of square miles the roads form a rough triangle)

lemonkettaz · 10 Jun 2006 at 19:22

erm...

the two lengths that are making the 90degree angle.. multiply by each other.. then half

area of a rectangle.. halved

Breamy · 10 Jun 2006 at 19:22

dont you like make it into a square then half it?

benjo · 10 Jun 2006 at 19:23

WxH / 2

edit: H being the perpendicular height from the base of the triangle... i think

yeh:

atpbx · 10 Jun 2006 at 19:24

should have gone to school more rather than playing football.

ballistic · 10 Jun 2006 at 19:24

wtf?
A triangle doesn't have a volume. A triangle is a 2D object and has an area.

The area is 1/2 bh

benjo · 10 Jun 2006 at 19:26

ballistic said:
wtf?
A triangle doesn't have a volume. A triangle is a 2D object and has an area.

Well he obviously meant area otherwise he would have stated it was a prism or something.. but he said it was the distance of a road..

BillytheImpaler · 10 Jun 2006 at 19:30

ballistic said:
wtf?
A triangle doesn't have a volume. A triangle is a 2D object and has an area.

The area is 1/2 bh

FACT!

Inquisitor · 10 Jun 2006 at 19:54

Well, he either meant the area of a triangle, or the volume of a triangular-based pyramid. I assume it's the latter, as he gave three dimensions, but I'm not exactly sure what these dimensions are :confused:

edit: scratch that, maybe he means a triangle with sides of length 11, 20, and 19? In this case, the area would be 10*sqrt(105), or 102.47 square miles

i know nothing · 10 Jun 2006 at 20:04

atpbx said:
how do i work out the volume of a triangle?

That would depend on how hard you hit it with the stick thingy. The harder you hit it the louder the "ding" will be.

marc_howarth · 10 Jun 2006 at 20:07

area of a triangle = 1/2 a b Sin c

Inquisitor · 10 Jun 2006 at 20:16

marc_howarth said:
area of a triangle = 1/2 a b Sin c

He doesn't have C though, so it's:

A = (a*b*sin(acos((a² + b² - c²) / 2ab))) / 2

Although that's a bit messy because accuracy is lost in the sin(acos(...)) stage...

Alternatively, you could use Heron's formula.

atpbx · 10 Jun 2006 at 20:19

Inquisitor said:
edit: scratch that, maybe he means a triangle with sides of length 11, 20, and 19? In this case, the area would be 10*sqrt(105), or 102.47 square miles

Aye i should have said area.

I just wanted a quick answer and wasnt thinking when i typed the question.

DaveyD · 10 Jun 2006 at 20:25

Inquisitor said:
He doesn't have C though, so it's:

A = (a*b*sin(acos((a² + b² - c²) / 2ab))) / 2

Although that's a bit messy because accuracy is lost in the sin(acos(...)) stage...

Alternatively, you could use Heron's formula.

Heron's is probably the better way for this, as it's pretty simple to use, and quick, compared to using sin and cos anyway.

Heron's formula, and other triangle stuff:
http://en.wikipedia.org/wiki/Triangle#Using_Heron.27s_formula

marc_howarth · 10 Jun 2006 at 20:29

Wow, never knew about Heron's formula before. Looks interesting

DaveyD · 10 Jun 2006 at 20:31

The answer is 102.4695 square miles anyway

MrMatteh · 10 Jun 2006 at 21:00

i know nothing said:
That would depend on how hard you hit it with the stick thingy. The harder you hit it the louder the "ding" will be.

Genius!

Dave · 10 Jun 2006 at 21:38

Isn't it Hero's formula? (not Heron's)

A = sqrt[s(s-a)(s-b)(s-c)] where s = (a+b+c)/2

edit/ looked at Wiki, never mind

WatchTower · 10 Jun 2006 at 21:42

WTF someone speak English I hate math it's evil and make my head hurt more than the hot weather does..

Dave · 10 Jun 2006 at 21:55

What is this "math" you speak of?

(you're not from the other side of the pond, are you?)

Volume of a triangle.

Man of Honour