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

Hint: A rangoli is a pattern or design with dots used to draw with the help of chalk power. We can find a number of such patterns in India. So, each pattern consists of many rows, each row has a number of dots that are designed in a straight line. We can find the number of dots in each pattern by multiplying the number of dots with the number of rows in a pattern or design Rangoli.

Complete step-by-step answer:
Given:
The number of dots for each row is \[x = 9\].
We know the equation to find the number of dots in the Rangoli for r rows is,
\[x \times r\]
On Substituting the values in the above equation, we get the value as,
\[9r\]
Therefore, the number of dots in r rows are 9r dots.
We also know the equation to find the number of dots in a 8 row Rangoli is,
\[8 \times x\]
Substituting the values in the above equation, we get the value of the number of dots for 8 rows.
\[\begin{array}{c}
8 \times x = 8 \times 9\\
 = 72
\end{array}\]
Therefore, the number of dots in 8 rows are 72 dots.
We also know the equation to find the number of dots in 10 row Rangoli is,
\[10 \times x\]
On Substituting the values in the above equation, we get the value of number of dots for 10 rows
\[\begin{array}{c}
10 \times x = 10 \times 9\\
 = 90
\end{array}\]
Therefore, the number of dots in 10 rows is 90 dots.
Therefore, the number of dots in r rows are 9r dots, the number of dots in 8 rows are 72 dots and the number of dots in 10 rows are 90 dots.

Note: In this type of question where you have to simply multiply the number of dots with the given value 9 dots always make sure that while substituting the values in the particular equation multiply the number of rows with the dots that consists in a row.