Question 663128
Note:
Area of a rectangle = L * B
Initial area before increment=30cm*15cm=450sqcm
New dimension is (x+30)cm by (x+15)cm
(X+30)(X+15)=450+144
X^2+45X+450=594
X^+45X-144=0
(X-3)(X+28)=0
X=3 or -28
Since it is distance our answer will be the positive value.
Answer=3cm