$a:b=c:d$ হলে যোজন প্রয়োগে —

• a$\dfrac{a+b}{b} = \dfrac{c+d}{d}$
• b$\dfrac{a-b}{b} = \dfrac{c-d}{d}$
• c$\dfrac{a}{a+b} = \dfrac{c}{c+d}$
• d$\dfrac{a+b}{a} = \dfrac{c+d}{c}$