What We Have Discussed

1. Cuboid and cube are regular prisms having faces, of which four are lateral faces, and the base and top.

2. If the length of a cuboid is l, breadth is b, and height is h, then:

- Total surface area of a cuboid = 2(lb + bh + )

- Lateral surface area of a cuboid = 2h(l + )

- Volume of a cuboid =

3. If the length of the edge of a cube is ‘l’ units, then

- Total surface area of a cube = 6l24l2

- Lateral surface area of a cube = 4l26l2

- Volume of a cube = l3l2

4. The volume of a pyramid is 13 volume of a right prism if both have the same base and same height.

5. A cylinder is a solid having two circular ends with a surface area. If the line segment joining the centers of the base and top is perpendicular to the base, it is called a right circular cylinder.

6. If the radius of a right circular cylinder is ‘r’ and height is ‘h’ then:

- Curved surface area of a cylinder = πrh

- Total surface area of a cylinder = 2πr(r + h)

- Volume of a cylinder = πr2hr2h

7. A cone is a geometrical shaped object with a as base, having a vertex at the top.

8. The length joining the vertex to any point on the circular base of the cone is called slant height (l).

• l2 = h2 + r2r2h2

9. If ‘r’ is the radius, ‘h’ is the height, ‘l’ is the slant height of a cone, then:

- Curved surface area of a cone = πrlrl

- Total surface area of a cone = πr(r + l)

10. The volume of a cone is 13rd the volume of a cylinder of the same base and same height. i.e., volume of a cone = 13πr²h

11. A is a geometrical object formed where the set of points are equidistant from the fixed point in space. The fixed point is called the of the sphere and the fixed distance is called the of the sphere.