The given information is,
To find the increase in area of the garden.
Formula we use,
→ Area = Length × Width
Area of the real garden is,
→ 5.4 × 1.5
→ 8.1 m
The new garden will be,
→ 5.4 × 1.2 = 6.48 m
→ 1.5 × 1.2 = 1.8 m
The area of the new garden is,
→ 6.48 × 1.8
→ 11.664
Then the increase in area of the garden,
→ 11.664 - 8.1
→ 3.564 m²
Hence, 3.564 m² is the increase in area.