Draw the graphs of the following equations on the same graph paper:

2x + y = 2, 2x + y = 6.


Find the coordinates of the vertices of the trapezium formed by these lines. Also, find the area of the trapezium so formed.

For equation, 2x + y = 2


First, take x = 0 and find the value of y.


Then, take y = 0 and find the value of x.


x



0



1



y



2



0



Now similarly solve for equation, 2x + y = 6


x



0



3



y



6



0



Plot the values in a graph and find the intersecting point for the solution.



Since, the line 2x + y = 6 cuts the line y - axis at A(0,6) and x - axis at B(3,0)


& the line 2x + y = 2 cuts the x - axis at C(1,0) and y - axis at D(0,2).


Thus, it is clear from the graph that ABCD forms a trapezium.


And the coordinates joining this trapezium are (0,6),(3,0),(1,0) and (0,2).


We can find the area of trapezium ABCD.


The formula to calculate area of a trapezium ABCD is:


Area(trap. ABCD) = Area(∆OAB) – Area(∆OCD)


= (1/2 × 3 × 6) – (1/2 × 1 × 2)


[ base(∆OAB) = 3 units & height(∆OAB) = 6 units


= 9 - 1 base(∆OCD) = 1 units & height(∆OCD) = 2units]


= 8 sq. units


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