The document discusses various geometric shapes, including cubes, cuboids, cylinders, cones, frustums, spheres, and hemispheres, emphasizing their surface areas and volumes. It defines key concepts like the surface area as the total exposed area of solid objects and provides insight into combinations of these solids in real life. Letstute, an e-learning company based in Mumbai, creates educational content and offers resources in multiple subjects.

2. Topics
1. Cube, Cuboid and Cylinder
2. Cone and Frustum
3. Sphere and Hemisphere
4. Combination of solids

3. Cube, Cuboid and Cylinder
Surface Area: It is the sum of total exposed area of
a three dimensional solid object. Its unit
can be in the form cm2, m2 etc.
Volume: It is the amount of space occupied by an
object. Its unit can be cm3, m3, etc.

4. Cuboid: A cuboid is the solid shape which has six
rectangle faces at right angles to each other.
Cube: A cube is a special form of cuboid which is
bounded by six equal square faces.
Right Circular Cylinder: A solid obtained by revolving a
rectangular lamina about one of its sides, is called as
Right Circular Cylinder.

6. Cone and Frustum
Cone: A cone is a three-dimensional geometric shape that tapers smoothly from
a flat circular base to a point called vertex.
We can also define it as, “A solid obtained by revolving a right angled
triangular lamina about
any side (except hypotenuse) is a right circular cone.”

7. Frustum: If the cone is cut off by a plane parallel to the base not
passing through vertex then we get the lower base portion as a
frustum of cone.

8. Sphere and Hemisphere

9. Hemisphere: A plane passing through the center of a sphere divides sphere into two
equal parts. Each part is called a hemisphere.

10. Combination of Solids
In real life we come across different objects
which are a combination of many shapes like
cube cuboid, cylinder, sphere, cone etc. In our
previous topics we have seen how to find the
areas and volumes of simple objects. Now we
will look at a few examples on how to find the
areas and volumes of combination of solids.

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