Robert D. Smith wrote: . . . Area = (base * height) / 2 . . .
You can work that out from side
a × side
b × sin(angleC) ÷ 2 but that requires use of the cosine rule to calculate the angle, if you have three sides. There is another method which seems to be called
Heron's formula.
They call
s semiperimeter, so
you should use the perimeter to calculate it..