Option 2 multiple each side by -5
See the diagram below.

is the height, and

is the slant height.
The height is the distance from the
base of the pyramid to the vertex (the top of the pyramid). It runs perpendicular to the base.
The slant height is the distance from the
base of the triangles which make up its sides to the vertex. It runs perpendicular to this base as well.
Answer:
6.75
Step-by-step explanation:
First, I just gave you the answer.
Second, just use it.
One decimeter equals 10 centimeters. So 3 decimeters equals 30 centimeters. They are equal.
The sequence is to multiply by -3. Therefore, you want to multiply by -3 which gives you 108. Since it is a negative by a positive the answer would be negative. The next term would be -108.