Radhika 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?
It is given in the question that,
Number of dots in 1 row = 9
Also,
Number of rows = r
Therefore,
Total number of dots in r rows = Number of rows × Number fo dots in a row
= 9 × r
= 9r
Hence,
Number of dots in 8 rows = 8 × 9 = 72
Also,
Number fo dots in 10 rows = 10 × 9 = 90