According to the meaning of the question, put a triangle with flowerpots, 9 flowerpots on each side.

A triangle has three angles, and each side has two angles.

Then there are 9-2=7 potted flowers on each side except the corner,

Then the total number of flowerpots used =7*3+3=24.

Extended data:

This kind of problem belongs to the typical tree planting problem in mathematics.

When planting trees on the closed line, the number of trees is equal to the number of segments, that is, the number of trees = the number of intervals.

Common formulas for planting trees:

(Plants at both ends): distance ÷ interval length+1= number of trees.

Interval length × (tree-1 )= total length

(Only plant one end): distance ÷ interval length = number of plants.

(Not planted at both ends): distance ÷ interval length-1 = number of plants.