The measure of one angel in a pair of complementary angels is 45 degrees, what's the measure of the other angle

Triangle xyz has vertices x(1,3), y(0,0)

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?

Ming says that 0.24 > 1/4 because 0.24= 2/4. which best explains mings error