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


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