7,2:88,2=0,4:x

To solve the proportion \( \frac{7.2}{88.2} = \frac{0.4}{x} \), you can use cross-multiplication. Cross-multiplying gives us: \[ 7.2 \cdot x = 0.4 \cdot 88.2 \] Calculating the right side: \[ 0.4 \cdot 88.2 = 35.28 \] Now, we have: \[ 7.2x = 35.28 \] To find \( x \), divide both sides by 7.2: \[ x = \frac{35.28}{7.2} \] Calculating the division: \[ x = 4.9 \] Thus, the value of \( x \) is \( 4.9 \).