Question

musa draws the area model shown to help him find 0.4 × 0.9.
does musas area model correctly represent 0.4 × 0.9?
yes, musas model shows 0.4 × 0.9.
how can musa change the model so that it shows 0.4 × 0.9?
change the side length of 0.3 to 0.4.
change the side length of 0.9 to 0.4.

Explanation:

Step1: Analyze the given area model

The blue shaded region has a height of 2 rows out of 10 ($0.2$) and width of 9 columns out of 10 ($0.9$), so it represents $0.2 \times 0.9$, not $0.4 \times 0.9$.

Step2: Identify the needed correction

To represent $0.4 \times 0.9$, the height (vertical side length) needs to be adjusted from $0.2$ to $0.4$. The option "Change the side length of 0.3 to 0.4" is the correct adjustment to reach the required $0.4$ vertical length.

Answer:

1. No, Musa's model does not show $0.4 \times 0.9$.
2. Change the side length of 0.3 to 0.4.