Across section of a cone taken perpendicular to the base and intersecting the apex of the cone is what shape? a. square b. triangle c. prism d. oval

B. Triangle

Step-by-step explanation:

Making the cone rest on its base on a flat surface and looking at the cross section from the side, the slant height gives the hypotenuse, the line perpendicular to the base  and joining the center of the base to the apex makes the height while the line joining the slant height to the center of the base gives the base of the right triangle formed.

Option C

Step-by-step explanation:

Let X be a discrete random variable that counts the number of siblings a randomly selected student has. Then the expected value of X is defined as:

Where is the probability that a randomly selected student has siblings

With

So in this case we know that

#of siblings 0        1        2        3        4         5

probability 0.20 0.65 0.08  0.04  0.02  0.01

Therefore:

The answer is the option C.