Call a, b, c be sides of the triangle, we have

\(\dfrac{a}{11}=\dfrac{b}{8}=\dfrac{c}{6}=\dfrac{a+b+c}{11+8+6}=\dfrac{100}{25}=4\)

=> a = 44, b = 32, c = 24

a mile = 5280 feets, an hour = 3600 seconds

30 miles per hour = 30 x 5280 feets per hour = 30 x 5280 / 3600 feets per second = 44 feets per second

The stage ith is \(i^2\)

So the number of dots at stage 47 is more than at the stage 27 is:

   \(47^2-27^2=\left(47-27\right)\left(47+27\right)=20.74=1480\)

1,

 2,

3, 

1 + 2 + 3 = 6,

2 + 3 + 6 = 11,

3 + 6 + 11 = 20,

6 + 11 + 20 = 35,

11 + 20 + 35 = 66.

20 + 35 + 66 = 121,

35 + 66 + 121 = 222,

66 + 121 + 222 = 409

The 11th is 409