 Hello and welcome to the session. In this session we discussed the following question which says the shape of the cross-section of a canal is a trapezium. If the canal is 10 meter wide at the top, 4 meter wide at the bottom and the area of its cross-section is 490 meter square by the depth of the canal. We know that area of a trapezium is equal to half into sum of the parallel sides of the trapezium into the distance between them, square units. So this is the area of a trapezium. This is the key idea that we use for this question. Now let's proceed with the solution. Consider this canal ABCD of trapezium shape at the top that is DC is 10 meters wide at the bottom, AB is 4 meters wide and we are given that the area of the cross-section of the canal is equal to 490 meter square. This BE is the depth of the canal and let this be equal to D meters. So we now have the area of the trapezium ABCD is equal to half into sum of its parallel sides that is AB plus CD into the distance between the two parallel sides that is BE. So this is equal to half into AB that is 4 plus CD or DC that is 10 into BE that we have taken as D. So this is equal to half into 14 into D meter square equal to now 2 7 times is 14 so this is equal to 7 D meter square is the area of the trapezium ABCD. Now it's already given to us that area of the cross-section of the canal is 490 meter square or we can say that area of the trapezium ABCD is given to us as 490 meter square. So we have 7 D is equal to 490 so from here we get D is equal to 490 upon 7 plus 7 70 times is 490 so this is equal to 70. That is the depth of the canal is equal to 70 meters. This is our final answer. So this completes the session hope you have understood the solution for this question.