James bought a pen for $170 and sold it to gain 20% on his cost price. How much was the item selling for after the increase

Sam claims that cos x =sin y if x and y are congruent angels. is sam correct ?

Ineed if you could explain and give me the answer you! this needs done

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.