The figure is made up for triangles drawn up to the Layer 3.
- How many triangles will there be if it is drawn up to Layer 5?
- If there is a total of 230 triangles, how many layers are there in the figure?
(a)
Pattern of the total number of triangles
Layer 1 = 1 (1 + 2 + 3 + 4) =
1 x
10 = 10
Layer 2 = 2 x (1 + 2 + 3 + 4) =
2 x
10 = 20
Layer 3 = 3 x (1 + 2 + 3 + 4) =
3 x
10 = 30
Formula:
Total number of triangles =
Layer Number x
10 Total number of triangles if it is drawn up to Layer 5
=
5 x
10 = 50
(b)
Number of layers if there is a total of 230 triangles
= 230 ÷
10 = 23
Answer(s): (a) 50; (b) 23
