Question 6579
If you know the lengths of the three sides of a triangle, there is a 
formula called Heron's formula

 Given the lengths of the sides  a,b ,c  
   
 semiperimeter 
 s= 1/2(a+b+c)
Heron's formula gives the area of the triangle as

Area =sqrt(s(s-a)(s-b)(s-c)