7:28=5,5:4x

To solve the equation \(7:28 = 5:4x\), we start by rewriting the ratios as fractions: \[ \frac{7}{28} = \frac{5}{4x} \] Next, simplify the left side: \[ \frac{7}{28} = \frac{1}{4} \] Now we have: \[ \frac{1}{4} = \frac{5}{4x} \] Cross-multiplying gives us: \[ 1 \cdot 4x = 4 \cdot 5 \] This simplifies to: \[ 4x = 20 \] To find \(x\), divide both sides by 4: \[ x = \frac{20}{4} = 5 \] Thus, the solution is: \[ \boxed{5} \]