The correct answer is option b. 3 + 3(n-1) = 3n.
Based on the image, the number of triangles in each design follows an arithmetic sequence.
- Design 1 has 6 triangles.
- Design 2 has 9 triangles (6 triangles from Design 1 + 3 more triangles).
- Design 3 has 12 triangles (9 triangles from Design 2 + 3 more triangles).
Therefore, the number of triangles for design n can be represented by the following expression:
This expression matches option b. 3 + 3(n-1) = 3n.
The question probable maybe:
Large rectangular patterns are designed using small square tiles that contain circles, stars, and triangles. Designs 1, 2, and 3 in this pattern are shown. If this pattern continues, which expression represent the number of triangles for design n?
a. 6 + 2(n-1) = 2n + 4
b. 3 + 3(n-1) = 3n
c. 6
d. 6n