Plz Help!! What is the area of the triangle? Enter your answer, in simplified radical form, in the box.

We can use Heron's  formula here

s = the semi-perimeter   = [9 + 4 +7 ]  / 2 =  20/2  =  10

The Area  is

√ [ s  (s - a) (s - b) (s - c)  ]         where a,b,c  are  the sides of the triangle

So we have

√ [ 10 * ( 10-9) (10 -4) (10 - 7) ]  =

√ [  10 * 1 * 6 * 3  ]  =

√ 180  =

√ [36 * 5 ] = 

6√5   units^2