What type of Distribution do these models represent (select all that supply)?​

What is the length of the unknown leg in the right triangle ?

Im literally having a mental breakdown

The distribution of the amount of money spent by students for textbooks in a semester is approximately normal in shape with a mean of $235 and a standard deviation of $20. according to the standard deviation rule, how much did almost all (99.7%) of the students spend on textbooks in a semester?