Page 281 - Start Up Mathematics_7

2. What is the horizontal cross-section of the plane with
a right circular cylinder (Fig. 1)? Will it change if the
cross-section is made slightly inclined (Fig. 2)? What
if the cylinder is replaced by a cone?

Fig. 1 Fig. 2
3. Construct a 3-D shape whose different views are as
given below:

Front Side Top

Some NCERT Textbook Questions

1. Here is an incomplete net for making a cube. Complete
it in at least two different ways. Remember that a cube
has six faces. How many are there in the net here?
(Give two separate diagrams. If you like, you may use
a squared sheet for easy manipulation.)
2. The dimensions of a cuboid are 5 cm, 3 cm and 2 cm. Draw three different isometric sketches
of this cuboid.
3. Three cubes each with 2 cm edge are place side by side to form a cuboid. Sketch an oblique
or isometric sketch of this cuboid.

4. What cross-sections do you get when you give a
(i) vertical cut (ii) horizontal cut
to the following solids?
(a) A brick (b) A round apple (c) A die

(d) A circular pipe (e) An ice cream cone
5. Examine if the following are true statements:

(i) The cube can cast a shadow in the shape of a rectangle.
(ii) The cube can cast a shadow in the shape of a hexagon.

Exemplar Problems

1. The name of the given solid is:
(a) triangular pyramid
(b) rectangular pyramid

(c) rectangular prism
(d) triangular prism

2. A solid that has two opposite identical faces and other faces as
parallelograms is a:
(a) prism (b) pyramid (c) cone (d) sphere

273