Study the pattern.

1. Find the total number of white and grey triangles in Figure 200.
2. Find the percentage of grey triangles in Figure 200. 

(a)
Total number of triangles.
Figure 1: 1 = 1 x 1
Figure 2: 4 = 2 x 2
Figure 3: 9 = 3 x 3
Figure 4: 16 = 4 x 4
Figure 5: 25 = 5 x 5

Formula:
Total number of triangles = Figure number x figure number

Total number of grey and white triangles for Figure 200
= 200 x 200
= 40000

(b)
Difference in the number of white and grey triangles.
Figure 1: 1 - 0 = 1
Figure 2: 3 - 1 = 2
Figure 3: 6 - 3 = 3
Figure 4: 10 - 6 = 4

Formula:
Difference in the number of white and grey triangles = Figure number

Number of white triangles = 1 u
Number of grey triangles = 1 u + Figure Number

Total number of triangles
= 200 x 200
= 40000

1 u + 1 u + 200 = 40000
2 u = 40000 - 200
2 u = 39800

1 u = 39800 ÷ 2 = 19900

Number of grey triangles
= 1 u + 200
= 19900 + 200
= 20100

Percentage of grey triangles in Figure 200
= ²⁰¹⁰⁰₄₀₀₀₀ x 100%
= 50.25%

Answer(s): (a) 40000; (b) 50.25%