The area of a right angled triangle is:
[tex]{ A }_{ 1 }=\frac { 1 }{ 2 } ab[/tex]
*Width would have to be equal to (a) and the length would have to be equal to (b).
The area of an irregular triangle would be:
[tex]{ A }_{ 2 }=\frac { 1 }{ 2 } ab\cdot \sin { C } [/tex]