Introduction To Graphs

Question

The following table gives the quantity of petrol and its cost.

Plot a graph to show the data.
Use the graph to find how much petrol can be purchased for Rs 800.

Solution

We draw axes and take a suitable scale on both the axes. To draw the graph, we take the following steps:
I. Mark the number litres of petrol along the horizontal axis.
II. Mark the cost of petrol (in rupees) along the y-axis.
III. Now, we plot the given points, i.e.
(10, 500); (15, 750); (20, 1000); (25, 1250)
IV. Join the points.
We find that the graph is a straight line.

Yes, we can find the quantity of petrol to be got in Rs 800, for this take a point on the y-axis (0,800). Through A draw BC parallel to x-axis to meet the graph at B. Now from B, draw BC Perpendicular x-axis.
As C corresponds to (16, 0).
Thus, 16 litre petrol can be bought for Rs 800.

Some More Questions From Introduction to Graphs Chapter

Can there be a time-temperature graph as follows? Justify your answer.

Ratana fell sick. Her doctor maintained a record of her hody temperature, taken every four hours. It is shown in the following time-temperature graph.
(a) During which period the temperature showed a rising trend?
(b) During which period the temperature showed a downward trend?
(c) At what time the temperature was highest?
(d) At what time the temperature was lowest?

Plot the following points on a graph sheet. Verify if they lie on a line:
(a) A (4, 0), B(4, 2), C(4, 6), D(4, 2.5)
(b) P(1, 1), Q(2, 2), R(3, 3), S(4, 4)
(c) K(2, 3), L(5, 3), M(5, 5), N(2, 5)

Draw the line passing through (2, 3) and (3, 2). Find the coordinates of the points at which this line meets the x-axis and y-axis.

Write the coordinates of the vertices of each of these adjoining Figures.

State whether True or False. Correct that are false.

The number of litres of petrol you buy to fill a car’s petrol tank will decide the amount you have to pay. Which is the independent variable here? Think about it.