Which ratios form a proportion?
a. 20/25, 14/21
b. 10/23, 18/7
c. 5/45, 4/36
d. 5/4, 4/5

Rockwell hardness of pins of a certain type is known to have a mean value of 50 and a standard deviation of 1.1. (round your answers to four decimal places.) (a) if the distribution is normal, what is the probability that the sample mean hardness for a random sample of 8 pins is at least 51?

The volume of a cube is 8 in to the 3rd power. how long is each side?

Find the number of real number solutions for the equation. x2 + 5x + 7 = 0 0 cannot be determined 1 2