Final answer:
The expression for the area of a rectangle with the length being 5 cm longer than the width is 'Area = width × (width + 5) cm'. which equals to 7.8125 square centimeters when calculated.
Step-by-step explanation:
The area of a rectangle is calculated by multiplying its length and width. If the length is 5 cm longer than its width, then if we call the width 'w', the length would be 'w + 5 cm'. Thus, the expression for the area of the rectangle would be width × (width + 5) cm, which corresponds to the formula Area = w × (w + 5). As the width of the rectangle is given as 1.25 cm, then the area would be 1.25 × (1.25 + 5), which equals to 7.8125 square centimeters when calculated.