With this kind of equation, you want to set up a ratio. So, in this case, let's say the top will be the height of the object, and the bottom in the shadow the object casts. So, it'll be x/23.5=6/4.7. You then cross-multiply and divide. So, you multiply 23.5*6, which is 141. Then you divide 141/4.7, which is 30. Hope that helped!
I think you would multiply 14m x 9m which is 126m and then you would multiply 2.4m and 3.8m which is 9.12m. Last you would subtract 9.12m from 126m which is 116.88m...I’m sry if this isn’t correct