“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} $”. Far East Journal of Mathematical Education 26, no. 2 (August 7, 2024): 71–77. Accessed January 5, 2026. https://pphmjopenaccess.com/fejme/article/view/2033.