find the direction cosines of the sides of the triangle whose vertices are (3,5,-4) (-1,1,2) and (-5,-5,-2)​

The size of a certain cell is 2.5*10^-9m. another cell is 1.5*10^3 times larger. how large is the larger cell in scientific notation?

One line passes through (-7,-4) and (5,4) . another line passes through the point (-4,6) and (6,-9)

The circumference of a redwood tree trunk is 20π ft, and it is 100 ft tall. what is the approximate volume of the redwood tree trunk? 1,000π ft3 10,000π ft3 4,000π ft3 40,000π ft3