CBSE Board Students Helpline

  Surface Areas and volumes   1) Two cubes of 12cm edge are joined end to end. Find the surface area of the resulting cuboid.     2) Three cubes of sides 6 cm edge are joined end to end. Find the surface area of the resulting cuboid.     3)   A solid sphere of radius 6cm is melted and recast into small spherical balls each of diameter 0.6cm. Find the number of balls thus obtained.   4) A sphere of diameter 7 cm is dropped in a right circular cylinder vessel partly filled with water. The diameter of the cylindrical vessel is 14 cm. If the sphere is completely submerged in water, by how much will the level of water rise in the cylindrical vessel?   5)   A hemispherical bowl of internal diameter 40 cm contains a liquid. This liquid is to be filled in cylindrical bottles of radius 4 cm and height 8 cm. How many bottles are required to empty the bowl?   6)   A conical vessel whose internal radius is 6cm and height is 25cm is full of water. The water is emptied into a cylindrical vessel wit

  Sample Paper – 2008 Class – X Subject – Mathematics   SECTION – A 2x10=20 If prove that If A and B are acute angles and sin A = cos B, Prove that A + B = 90 0 . If Show that Find the value of c such that the equation 4x 2 - 2(c + 1) x + (c + 4) = 0 has real and equal roots.    Prove Solve for x:               4x 2 – 4a 2 x + (a 4 – b 4 ) = 0               The sum of first 15 terms of an A.P. is 105 and the sum of next 15 terms is 780. Find the first 3 terms of the    A.P. Evaluate Find the 20th term from the last term of the A.P. 3, 8,13, ……………, 253. Find the sum of all natural numbers between 100 and 1000 (excluding both) which are divisible  by 2 as well as 5.   SECTION-B 3X10=30 If the list price of a book is reduced by Rs 5, a person can buy 5 more books for Rs 300. Find the o riginal list price of the book. Find four numbers in A.P., whose sum is 20 and sum of their squares is 120. In a cricket match McGrath took one wicket less than twice the number of wickets taken

Topic: Triangles Time: 2 Hours Answer all the questions. Short Answer questions   Prove that the line joining the midpoints of two of the sides of a triangle is parallel to the other side and half of it. C D The diagonals of a quadrilateral ABCD intersect at a point O such that . Prove that ABCD is trapezium. In the fig if AB || DC|| EF. Prove that . F E If P E ||RS, prove that D P OE ~ D ROS S E QQQQQ Q P B A     R          A girl of height 120cm is walking past a lamp post at a speed of 1.5 meters per second finds the length of the shadow after 5 seconds to be 1 25cm. Find the height of the lamp post. S and T are points on sides PR and QR of D PQR such that Ð P = Ð RTS. Prove that D RPQ ~ D RTS. If D ABC ~ D DEF and their areas are 196 cm 2 and 225cm 2 respectively. If FD = 22.5cm find CA P S If the areas of two similar triangles are equal, prove that the triangles are congruent. O A B Find  Ð ABP and Ð BAQ in the figure if      Ð OPS = 35 ° and Ð SOB = 125 °       A ladd

Topic: Triangles Time: 2 Hours Answer all the questions. Short Answer questions   Prove that the line joining the midpoints of two of the sides of a triangle is parallel to the other side and half of it. C D The diagonals of a quadrilateral ABCD intersect at a point O such that . Prove that ABCD is trapezium. In the fig if AB || DC|| EF. Prove that . F E If P E ||RS, prove that D P OE ~ D ROS S E QQQQQ Q P B A     R          A girl of height 120cm is walking past a lamp post at a speed of 1.5 meters per second finds the length of the shadow after 5 seconds to be 1 25cm. Find the height of the lamp post. S and T are points on sides PR and QR of D PQR such that Ð P = Ð RTS. Prove that D RPQ ~ D RTS. If D ABC ~ D DEF and their areas are 196 cm 2 and 225cm 2 respectively. If FD = 22.5cm find CA P S If the areas of two similar triangles are equal, prove that the triangles are congruent. O A B Find  Ð ABP and Ð BAQ in the figure if      Ð OPS = 35 ° and Ð SOB = 125 °       A ladd