PROOF WITHOUT WORDS: $a, B, C, d>0$; $ \frac{a}{b}=\frac{c}{d} \Rightarrow \frac{a}{b}=\frac{c}{d}=\frac{s a+t c}{s b+t D} $. FEJME 2024, 26 (2), 71-77. https://doi.org/10.17654/0973563124008.