Answer: Choice A) cone
One way to picture this is to think of a propeller. As the propeller spins, it carves out a 3D space even though the blade is "2D" in a sense.
If we spin everything around segment BC, we get a 3D cone forming. The base of the cone is vertical and it has a radius of AC. The height of the cone is segment BC. It might help to rotate the paper 90 degrees clockwise so that BC is vertical.
4.86 is the answer to you're question.
One way to do this is use the fact that the exterior angles of all polygons add up to 360 degrees
So an exterior angle of a regular octagon = 360 / 8 = 45 degrees.
So each interior angle = 180 - 45 = 135 degrees
so total measure of all angles in octagon = 8 * 135 = 1080 degrees
Answer:
D
Step-by-step explanation: