 Hello and welcome to the session. The question says it is required to make a closed cylindrical tank of height 1 meters and base diameter 140 cm from a metal sheet. How many square meters of sheet are required for the same? So first let us learn the formula to calculate the total surface area of the cylinder of radius r cm which is the radius of the base and height 8 cm. So this is equal to pi r into r plus h. So with the help of this formula we are going to solve the above problem so this is our key idea. Let us now start with the solution. So here we are given of cylinder. Let us denote it by small h is equal to 1 meters and since 1 meter is equal to 100 cm therefore we have h is equal to 100 cm. Also we are given that base diameter is equal to 140 cm so this implies that base radius let us denote it by small r is equal to 140 cm upon 2 so equal to 70 cm and we are required to find how many square meters of the sheet are required for the same. So we have to find the total surface area of the cylinder and that will be equal to the area of sheet required. So this is equal to 2 pi r into r plus h. Now substituting the values of pi r and h we have 2 into 22 upon 7 into r is 70 into 70 plus 100 so we further have 2 into 22 is 44 7 tens are 70 so we have into 10 into 170 so we have 440 into 170 which further gives 74800 cm square. Now since 1 cm is equal to 1 upon 100 meters the therefore 1 cm square is equal to 1 upon 100 into 100 that is 10000 meters square. Thus the total surface area which is in cm square to change it into meters square we have to divide it by 10000 and this gives us 748 meters square right therefore her answer is the area of sheet required in square meters is 748 meters square so this completes the session bye and take care.