7,2:2,4=0,9:x

To solve the equation \( \frac{7.2}{2.4} = \frac{0.9}{x} \), we can start by simplifying the left side:

1. Calculate \( \frac{7.2}{2.4} \): \[ \frac{7.2}{2.4} = 3 \]

Now, we have: \[ 3 = \frac{0.9}{x} \]

2. Cross-multiply to solve for \( x \): \[ 3x = 0.9 \]

3. Now, divide both sides by 3 to isolate \( x \): \[ x = \frac{0.9}{3} = 0.3 \]

Therefore, the value of \( x \) is \( 0.3 \).