 Hello and welcome to the session. In this session we discussed the following question which says, the length, breadth and height of a box are respectively 8 meters, 4 meters and 2 meters. Find the length of the greatest rod that can be put in it. Before we move on to the solution, let's recall the formula to calculate the length of the diagonal of the cuboid and this is equal to square root of a square plus b square plus c square where this a is the length of the cuboid, b is the breadth of the cuboid and c is the height of the cuboid. This is the key idea that we use in this question. Let's proceed with the solution now. In the question we are given the length, breadth and height of a box and we need to find the length of the greatest rod that can be put in it. Length of the greatest rod that can be put in it can be found out by finding the length of the diagonal of this box. Now here we have the length of the box is 8 meters so we take length of the box say a be equal to 8 meters then breadth of the box say b is given as 4 meters so this is equal to 4 meters then height of the box say c is given as 2 meters so this is equal to 2 meters now length of the greatest rod which can be put in the box is equal to the length of the diagonal now as this box is cuboid so the length of its diagonal is given by square root of a square that is t length square plus the breadth square which is b square plus the height square that is c square now putting the values for a b and c we get this is equal to square root of 8 square plus 4 square plus 2 square further we get this is equal to square root of 64 plus 16 plus 4 or you can say this is equal to square root of 80 plus 4 that is we get this is the square root of 84 now square root of 84 is equal to 2 root 21 then we have found out the square root of 21 as 4.58 till two decimal places so this is equal to 4.58 meters so we get the length of the diagonal of the box as 4.58 meters which means that the length of the greatest rod which can be put in the box is 4.58 meters thus our final answer is length of the greatest rod which can be put in the box is equal to 4.58 meters this is our final answer this completes the session hope you have understood the solution of this question