Question

Radha is drawing a dot Rangoli (a beautiful pattern of lines joining dots) with chalk powder. She has $9$ dots in a row. How many dots will her Rangoli have for $r$ rows? How many dots are there if there are $8$ rows? If there are $10$ rows?

Answer 1

Given that

Number of dots in $1$ row $=9$

Total number of dots in $\mathrm{r}$ rows = Number of dots in $1$ row × number of rows

$=9r$

Number of dots in $8$ rows $=8\times 9$ $=72$

Number of dots in $10$ rows $=10\times 9$ $=90$

Hence

The number of dots in $8$ rows are $72$ and the number of dots in $10$ rows are $90$