what is 45999999999999999x 9999999999999999999999 divided by 56 plus 99 divided by 2 and then multiplied by 99999999999999999999999999999999999 99999999999999999999999999999999999 99999999999999999999999999999999999 9999999999999999999999999999999 i want to know

What are the measures of ∠a, ∠b, ∠c and ∠d? explain how to find each of the angle measure.

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.

Factor the expression using gcf 9b+45