[question] simple and easy tringle area

Liveit

Hi,

Im asking this question just to be certain and sure, I know its basic.
To find the area of a triangle you ise the formula 1/2 ab SinC.
To find the area of a right angle triangle you can use the formula 1/2 base x height

Am I right with that?

Thanks in advance!

(damn i spelled triangle as tringle in the heading *facepalm)

Eliot Rosewater

Yes! In fact the second formula can be derived from the first.


Area = [LATEX]\displaystyle \frac{1}{2}ab\sin{\theta}[/LATEX]

In a right angle triangle the area between a, the base, and b, the height, is 90 degrees. Sin(90)=1.

Hence

Area = [LATEX]\displaystyle \frac{1}{2}ab\sin{90}[/LATEX]

Area = [LATEX]\displaystyle \frac{1}{2}ab(1)[/LATEX]

Area = [LATEX]\displaystyle \frac{1}{2}ab[/LATEX]

MathsManiac

The area of a triangle is always half the base by the height, not just in right-angled triangles.

The only difference is that in the case of a right triangle, the height is one of the sides (assuming you haven't taken the hypotenuse as the base).

Liveit

Ah I never realised it could be derived like that, thanks elliot and MathsManiac.
Its all cleared up now