I’m so confused what this means it’s geometry and well this just doesn’t make sense so if you know geometry well plz take a look at this

Suppose the radius of a circle is 16. what issuppose the radius of a circle is 16. what is its circumference its circumference

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.

Which of the following transformations will always produce a congruent figure?