The volume of the frustum of regular triangular pyramid is 135 m3. the lower base is an equilateral triangle with an edge of 9 m. the upper base is 8 m above the lower base. what is the upper base edge, in m? .

Ascientist wants to use a model to present the results of his detailed scientific investigation. why would a model be useful? a )because the model makes the concepts easier to understand b) because the model is easy to put together and to use c) because the model prevents other scientists from asking questions d) because the model requires the audience to pay full attention to it i don't know what to choose because between a and d a is much more likely than d because it only wants to get the attention of the audience. i'm confuse.