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Last updated at Sept. 10, 2018 by Teachoo

Transcript

Ex 11.1, 7 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 ? Here, Number of dots in 1 row = 9 dots Number of dots in 2 row = 9 × 2 = 18 dots Number of dots in 3 rows = 9 × 3 = 27 dots So, Number of dots = 9 × Number of rows Writing number of rows = r Number of dots = 9 × r = 9r where r = number of rows If there are 8 rows Then, r = 8 Number of dots = 9r = 9 × 8 = 72 There will be 72 dots in 8 rows If there are 10 rows Then, r = 10 Number of dots = 9r = 9 × 10 = 90 There will be 90 dots in 10 rows. This is answer does not match from back. If we have made any mistake, please let us know

About the Author

Davneet Singh

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 9 years. He provides courses for Maths and Science at Teachoo.