Explanation:
Part A: Let see what number we can multiply by 3 to get 13.5
![3x = 13.5](https://img.qammunity.org/2022/formulas/mathematics/college/2og5yr5ei85l3ptewleuuar30pepegvrc5.png)
![x = 4.5](https://img.qammunity.org/2022/formulas/mathematics/high-school/303fd0h81v1dag2cdn54nkl223ectlmp2h.png)
so our answer is 4.5
Part B : Set up the proportion
3 and 13.5 correspond with each other and the question mark side corresponds with the 9 cm side.
let x = the side we are trying to find
![(3)/(x) = (13.5)/(9)](https://img.qammunity.org/2022/formulas/mathematics/college/8buwqg9kpfzbld4io1yn1wusnogzzp2k97.png)
Cross multiply
![27 = 13.5x](https://img.qammunity.org/2022/formulas/mathematics/college/r65162jde6jclh5xs8fvygjwcszkxhd77c.png)
![x = 2](https://img.qammunity.org/2022/formulas/mathematics/college/17rxgdi00d0xuclfg1jq4oqczj0zgbwqpq.png)
so our answer is 2.