Ten balls, each marked with a number from 0 to 9 are placed in a bag and two balls are taken out at random.
Find the probability that the sum of the numbers is 4.

On a architect's drawing of a house, 1 inche representa 1.5

Determine whether the following statements are true and give an explanation or counterexample. bold a. when using the shell method, the axis of the cylindrical shells is parallel to the axis of revolution. bold b. if a region is revolved about the y-axis, then the shell method must be used. bold c. if a region is revolved about the x-axis, then in principle it is possible to use the disk/washer method and integrate with respect to x or the shell method and integrate with respect to y.

The reflexive property of congruence lets you say that ∠pqr ≅