The fourth proportion of 12, 24 and 45 is:A25B90C60D30Answer: B. 90 Read Explanation: 12,24,45,?12,24,45,?12,24,45,?=24×4512=108012=\frac{24\times45}{12}=\frac{1080}{12}=1224×45=121080=90=90=90 Read more in App