#### Answer

56%

#### Work Step by Step

Lets take the initial base of a rectangle be b
and the height be h
Base is increased by 20% of b
therefore final Base = 1.2 b
The altitude is increased by 30 % of h
Final altitude =1.3 h
The area of rectangle whose base has length b and altitude has length h is given by A = bh
Initial area of rectangle = bh
Final area of rectangle = (1.2b) * (1.3h)
= 1.56bh
Increase in area of rectangle in percentage = $\frac{final area - initial area}{initial area}$ * 100
=$\frac{1.56bh - bh}{bh}$ * 100
=$\frac{0.56bh}{bh}$ * 100
= 0.56 * 100 = 56%
therefore 56% area is increased