The half-life of radium is 1690 years. If 20 grams are present now, how much will be present in 250 years?
? grams
(Do not round until the final answer. Then round to the nearest thousandth as needed.)

Module 10 coordinate proof using slope and distance answers is quadrilateral abcd a parallelogram? explain how you know.

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 table represents points on the graph of h(x) = 3√-x+2?