 Hello and welcome to the session. Today I will help you with the following question. The question says verify Uless formula for this solid. First let's see what the Uless formula is. Uless formula is F plus V minus E is equal to 2 where F is the number of faces of the polyhedron V is the number of vertices of the polyhedron is the number of edges of the polyhedron. This is the key idea for this question. Now let's move on to the solution. Number of faces that is F in this figure would be, now this is one face, this is the second face, third face, fourth face, one face along this edge, one face along this edge and one is the base. So in all we have F equal to 7. Then the number of vertices that is V is equal to, this is one vertex 2, 3, 4, 5, 6, 7, 8, 9 and one vertex is behind. So in all we have 10 vertices that is V is equal to 10. Then the number of edges that is E would be equal to, now this is one edge 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 and three edges are behind. So in all we have 15 edges that is E is equal to 15. By Uless formula we have F plus V minus E is equal to 2. We consider the LHS that is F plus V minus E and now we substitute the values of F, V and E. This becomes equal to F is 7. So we have 7 plus V is 10 minus E is 15 which is equal to 17 minus 15 and this is further equal to 2 that is equal to RHS of the Uless formula. Hence Uless formula is verified. Hope you enjoyed the session. Have a good day.