What is the area of half circle with a radius of 40 cm?

PLEASE HELPPP ILL GIVE BRAINLIEST

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.

What is 1/3x5 on anuber line what does it look like on a number line

Which strategy is used by public health to reduce the incidence of food poisoning?