Since the graph is a linear function, we're going to use the slope formula solve this:
Note I am replacing m with k

Inserting 2 points from the graph, let's use (1,8) and (2,16).

k=8
Zero is equal to its negative
Answer:
Right-triangle
Step-by-step explanation:
Take a right triangle for example, then twist it 360 degrees, keeping the longest leg at the center of rotation. It will then form a cone.