**Selina Concise Class 8 Math Chapter 21 Surface Area Volume and Capacity Exercise 21C Solution**

Concise Mathematics – Class 8 Selina Exercise 21C Solution by experts | 21C Selina Concise Solution Class 8 | Class 8 Selina Concise Ex 21C Page 241 Solution | RK Bansal Class 8 ICSE Book Solution Online.

**(1) The edges of three solid cubes are 6 cm, 8 cm and 10 cm. These cubes are melted and recasted into a single cube. Find the edge of the resulting cube.**

**(2) Three solid cubes of edges 6 cm, 10 cm and x cm are melted to form a single cube of edge 12 cm. find the value of x.**

**(3) The length of the diagonal of a cube is 8√3 cm. Find its:**

**(i) edge (ii) total surface area (iii) volume**

**(4) A cube of edge 6 cm and a cuboid with dimensions 4 cm x X cm x 15 cm are equal in volume. Find:**

**(i) the value of x.**

**(ii) total surface area of the cuboid.**

**(iii) total surface area of the cube.**

**(iv) which of these two has greater surface and by how much?**

**Solution: **

**(5) The capacity of a rectangular tank is 5.2 meter cube and the area of its base is 2.6 x 10 ^{4} cm^{2}, find its height (depth).**

**(6) The height of a rectangular solid is 5 times its width adn its length is 8 times its height. If the volume of the wall is 102.4 cm ^{3}, find its length.**

**(7) The ratio between the lengths of the edges of two cubes are in the ration 3:2. Find the ratio between their:**

**(i) total surface area**

**(ii) volume**

**Solution: **

**(8) The length, breadth and height of a cuboid (rectangular solid) are 4:3:2**

**(i) If its surface area is 2548 centimeter square, find its volume.**

**(ii) If its volume is 3000 meter cube, find its surface area.**

**Solution: **