question_answer 1)

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:

                Given, the number of rows = r and the number of dots in one row i.e. r  = 1 is 9 \[\times \] 1 = 9 \[\therefore \] the number of dots in 2 rows i.e. r  = 2 is 9\[\times \]2 = 18 the number of dots in 3 rows i.e. r = 3 is 9 \[\times \] 3 = 27 \[\therefore \] Total number of dots in r rows is = 9 \[\times \] r = 9r Now, if there are 8 rows i.e. r = 8, then the number of dots = 9 \[\times \] 8 = 72 dots and for r = 10, the number of dots = 9 \[\times \] 10 = 90 dots.