As shown in the pie graph, Ajay Bhai bought 3600-kilogram grains from the market for his shop during the day, answer the following question:
How many kilograms of Castor-seeds are there?

A) 700 kilograms
B) 800 kilograms
C) 900 kilograms
D) 950 kilograms

Hint: The pie-chart is a diagram model question, it will consist of different items with a certain percentage, we have to find the quantity with the help of the percentage compared with the whole amount. In this diagram, the quantity is provided in terms of degrees of the circle so firstly we have to convert the degrees into the percentage and can find the required output.

Complete step-by-step answer:
The total kilogram Ajay Bhai bought is $x = 3600$ kilograms.
The total that a circle consists of is $360^\circ $, but if we take the total quantity for $100\% $.
Now, by observing the pie-chart, we know the Castor seeds quantity is $90^\circ $, converting it into percentage we will get,
$ \Rightarrow \dfrac{{90^\circ }}{{360^\circ }} \times 100\% $
Simplify the terms,
$ \Rightarrow 25\% $
Let us assume, $y = 25\% $.
The equation to find the quantity of Castor-seeds is given by,
$\dfrac{{x \times y}}{{100}}$
Substituting the values in the equation, we will get,
$ \Rightarrow \dfrac{{3600 \times 25}}{{100}}$
Simplify the terms,
$\therefore 900$ kilograms
So, the quantity of Castor-seeds bought is 9000 kilograms.

Hence, option (C) is the correct answer.

Note: In this solution, we have converted the degrees to percentage and then calculated the quantity bought but we can solve this question without converting the degree to percentage.
Firstly, we have to find the quantity for each degree (it can be calculated by dividing the total quantity bought by $360^\circ $, we get
$ \Rightarrow \dfrac{{3600}}{{360}}$
Simplify the terms,
$ \Rightarrow 10$ kilograms
then we should multiply by $90^\circ $to get the amount of Castor seeds,
$ \Rightarrow 10 \times 90 = 900$ kilograms.
So, the quantity of Castor-seeds bought is 900 kilograms.
Hence, option (C) is the correct answer.