Let the altitude of the triangle be x cm.
By the given condition, the base of the triangle is (x + 4) cm.
Now, the area of the triangle = 12(base)×(height)
By the given condition 12(x+4)(x)=48
→x2+4x−96=0→(x+12)(x−8)=0
→x=−12 or 8
But x = 12 - is not possible (since the length should be positive)
Therefore, x = 8 and hence, x+4=12.
Thus, the altitude of the triangle is 8 cm and the base of the triangle is 12 cm.