Make an equal-sided triangle with toothpicks or drawing on paper.
Find the distance around it, the perimeter (3 units).
Adjoin another equilateral triangle by adding 2 more toothpicks.
Record the perimeter of the new shape: 5 units.
Adjoin another equilateral triangle by adding 2 more toothpicks, and again record the perimeter.
Keep track of the information in a table (see handout linked below).
What patterns do you see?
How is the perimeter growing at each new stage?
What is each perimeter compared to the number of triangles?
See the attached 5-min. video from the Math for Adults Foundation youtube page for the answer!
Handout: Math for Parents Curriculum: Thinking in Patterns, Session 2 BLM7. https://935d0577-c320-498f-9870-ecb0a12ac47d.filesusr.com/ugd/9254e5_aef9cfde0b3a4d329f19aac6375a8b38.pdf
Video solution: https://www.youtube.com/watch?v=RhbgU3mocdc&feature=youtu.be