Answer: 7.3 in
Step-by-step explanation:
To find the the value of x, we will simply use the formula of area of a triangle, substitute the values and then solve.
From the diagram above, the height of the triangle is x and also the base of the triangle is also x, the area of the triangle is  27 sq. in
Area of a triangle =   base × height
  base × height
               27             =   ×   x ×  x
   ×   x ×  x
               27               =  ×       x²
   ×       x²
                 27              =    
           cross  multiply 
                     2   ×  27   =  x²
                         54    =    x²
Take the square roots of both-side
                     √54       =       √x²
                       7.3        =         x
                        x         =       7.3
Therefore the value of x is 7.3 in.