7/8 / 2/5 is equal to 7/8 x 5/2 which equals 35/16, 16 goes into 35 twice so there are 2 wholes there is a remaining of 3 so we put it as a fraction over 16 
the answer is 2 3/16 
        
             
        
        
        
Extend means to increase, add length to it, ADD.
       2.826 
+    1.46
--------------
       4.286
        
             
        
        
        
That's is depend from the author of the equation. But most time there is need to multiply value X into constant before.
In other words it look likes
y=2*x-3
        
             
        
        
        
Area of the triangle = (1/2)*base*height
base = x
height = altitude = x+6
Area of the triangle = (1/2)*x*(x+6) = 108
(1/2)*x*(x+6) = 108
x²+6x-216 =0
(x+18)(x-12)=0
x=-18, or x=12
We can use only positive value, so x=12.
Base =12 cm.