How are the triangles similar please help

Abacteria population is tripling every hour. by what factor does the population change in 1/2 hour? select all that apply

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.

Look at triangle wxy what is the length (in centimeters) of the side wy of the triangle?