Question

16. A triangle pattern is shown below.

(Image 1)

The perimeter of each figure in the pattern is shown in the table below.

(Image 2)

Which equation relates the number of triangles in the figure (n) to the perimeter of the figure (P)?

Answer 1

D

Explanation:

P = 7n + 20

Answer 2

P = 7n + 20

consider the results of figure to perimeter

1 → 27

2 → 34

3 → 41

the difference between perimeters is 41 - 34 = 34 - 27 = 7

multiplying the figure number by the difference gives

1 × 7 = 7 ← require 27 thus add 20

2 × 7 = 14 ← require 34 thus add 20

3 × 7 = 21 ← require 41 thus add 20

Hence the required equation is

P = 7n + 20