Page 127 - Touchpad Mathematics_Ver1.0_C4
P. 127
plAne And CuRved SuRfACeS
The part of an object which we see, touch and feel is known as the Surface. A surface
can be plane (or flat) or curved.
1. Some objects have only a plane surface.
2. Some objects have only a curved surface.
3. Some objects have both plane and curved surfaces.
faces, edges and Corners of a Solid
l face: The surface of a solid shape is made up of faces.
The face of a solid could be plane or curved.
l edge: The line where two faces meet is called an edge.
The edge of a solid could be straight or curved.
l Corner: The point where three edges meet is called a
corner or vertex.
Cube
l A cube has 6 plane faces having the same shape and size.
l It has 8 corners or vertices.
l It has 12 edges. All the edges are straight and of the
same length.
Cuboid
l A cuboid has 6 plane faces but all are not the same
shape and size. The opposite faces of a cuboid are the
same shape and size.
l It has 8 corners.
l It has 12 edges (straight) but all are not equal. The opposite edges are equal.
difference between a cube and a cuboid
l In a cuboid, the opposite faces are the same shape and size. In a cube, all the
faces are the same shape and size.
l In a cube, all the edges are equal, whereas in a cuboid, the edges can be
different sizes.
125
Geometry
