Fractals and Visualising Solids | FIO

Question 11

Find the front view, top view and side view of each of the following solids, fixing its orientation with respect to the vertical, horizontal and side planes: cube, cuboid, parallelepiped, cylinder, cone, prism, and pyramid. If needed, see the next problem for clues.

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Solution

We can understand a 3D object by looking at it from different directions, creating 2D pictures called views.

Step 1 — Understanding Views

Let us imagine a 3D object placed in front of us. We can look at it from different angles. Each angle gives us a flat, 2D picture of the object.

The front view is what we see when we look directly at the object from the front. The top view is what we see when we look directly down on the object from above. The side view is what we see when we look directly at one side of the object. For this problem, we will assume a standard orientation for each solid, usually with its main axis vertical.

Diagram 1

Step 2 — Cube Views

Let us consider a cube with each side of length ll. We place the cube so its faces are perfectly aligned with our viewing directions.

When we look at the cube from the front, we see one of its square faces. This square has dimensions ll by ll.

When we look down on the cube from the top, we see its top square face. This square also has dimensions ll by ll.

When we look at the cube from the side, we see one of its side square faces. This square also has dimensions ll by ll.

Front view: square l×l, Top view: square l×l, Side view: square l×l\boxed{\text{Front view: square } l \times l \text{, Top view: square } l \times l \text{, Side view: square } l \times l}

Diagram 2

Step 3 — Cuboid Views

Let us consider a cuboid with length ll, breadth bb, and height hh. We place the cuboid with its length along the front-back direction, breadth along the left-right direction, and height vertically.

When we look at the cuboid from the front, we see a rectangular face. This rectangle has length ll and height hh.

When we look down on the cuboid from the top, we see its top rectangular face. This rectangle has length ll and breadth bb.

When we look at the cuboid from the side (e.g., the right side), we see a rectangular face. This rectangle has breadth bb and height hh.

Front view: l×h rectangle, Top view: l×b rectangle, Side view: b×h rectangle\boxed{\text{Front view: } l \times h \text{ rectangle, Top view: } l \times b \text{ rectangle, Side view: } b \times h \text{ rectangle}}

Diagram 3

Step 4 — Parallelepiped Views

A parallelepiped is a 3D shape where all six faces are parallelograms. Let us imagine it resting on one of its parallelogram bases.

When we look at the parallelepiped from the front, we see one of its parallelogram faces. This is a parallelogram.

When we look down on the parallelepiped from the top, we see its top face. This is also a parallelogram.

When we look at the parallelepiped from the side, we see one of its side faces. This is also a parallelogram.

Front view: parallelogram, Top view: parallelogram, Side view: parallelogram\boxed{\text{Front view: parallelogram, Top view: parallelogram, Side view: parallelogram}}

Diagram 4

Step 5 — Cylinder Views

Let us consider a cylinder with its axis placed vertically. Imagine it standing upright, like a soda can.

When we look at the cylinder from the front, we see its curved surface. This appears as a rectangle. The width of this rectangle is the diameter of the cylinder's base, and its height is the cylinder's height.

When we look down on the cylinder from the top, we see its circular top base. This is a circle.

When we look at the cylinder from the side, we again see its curved surface. This also appears as a rectangle, identical to the front view.

Front view: rectangle, Top view: circle, Side view: rectangle\boxed{\text{Front view: rectangle, Top view: circle, Side view: rectangle}}

Diagram 5

Step 6 — Cone Views

Let us consider a cone with its axis placed vertically. Imagine it standing upright, with its circular base on the ground and its tip pointing up.

When we look at the cone from the front, we see its triangular shape. This appears as an isosceles triangle. The base of this triangle is the diameter of the cone's base.

When we look down on the cone from the top, we see its circular base. We also see the very tip (apex) of the cone in the center of the circle.

When we look at the cone from the side, we again see its triangular shape. This also appears as an isosceles triangle, identical to the front view.

Front view: isosceles triangle, Top view: circle (with center dot), Side view: isosceles triangle\boxed{\text{Front view: isosceles triangle, Top view: circle (with center dot), Side view: isosceles triangle}}

Diagram 6

Step 7 — Prism (square base, axis vertical) Views

Let us consider a prism with a square base, and its axis placed vertically. Imagine it standing upright, with its square base on the ground.

When we look at this prism from the front, we see one of its rectangular side faces. This is a rectangle.

When we look down on the prism from the top, we see its square top base. This is a square.

When we look at the prism from the side, we see another rectangular side face. This is also a rectangle, identical to the front view because the base is square.

Front view: rectangle, Top view: square, Side view: rectangle\boxed{\text{Front view: rectangle, Top view: square, Side view: rectangle}}

Diagram 7

Step 8 — Pyramid (square base, axis vertical) Views

Let us consider a pyramid with a square base, and its axis placed vertically. Imagine it standing upright, with its square base on the ground and its apex pointing up.

When we look at this pyramid from the front, we see one of its triangular faces. This appears as an isosceles triangle.

When we look down on the pyramid from the top, we see its square base. We also see the edges connecting the corners of the base to the apex, which appear as diagonals within the square.

When we look at the pyramid from the side, we again see one of its triangular faces. This also appears as an isosceles triangle, identical to the front view.

Front view: isosceles triangle, Top view: square (with diagonals), Side view: isosceles triangle\boxed{\text{Front view: isosceles triangle, Top view: square (with diagonals), Side view: isosceles triangle}}

Diagram 8

Answer

(a) Cube: Front view, Top view, and Side view are all squares of dimension l×ll \times l. (b) Cuboid: Front view is l×hl \times h rectangle, Top view is l×bl \times b rectangle, Side view is b×hb \times h rectangle. (c) Parallelepiped: Front view, Top view, and Side view are all parallelograms. (d) Cylinder (axis vertical): Front view is a rectangle, Top view is a circle, Side view is a rectangle. (e) Cone (axis vertical): Front view is an isosceles triangle, Top view is a circle (with center dot), Side view is an isosceles triangle. (f) Prism (square base, axis vertical): Front view is a rectangle, Top view is a square, Side view is a rectangle. (g) Pyramid (square base, axis vertical): Front view is an isosceles triangle, Top view is a square (with diagonals), Side view is an isosceles triangle.

More questions in FIO

Q1

Draw the initial few steps (at least till Step 2) of the shape sequence that leads to the Sierpinski Triangle.

Q2

Find the number of holes, and the triangles that remain at each step of the shape sequence that leads to the Sierpinski Triangle.

Q3

Find the area of the region remaining at the nnth step in each of the shape sequences that lead to the Sierpinski fractals. Take the area of the starting square/triangle to be 1 sq. unit.

Q4

Draw the initial few steps (at least till Step 2) of the shape sequence that leads to the Koch Snowflake.

Q5

Find the number of sides in the nth step of the shape sequence that leads to the Koch Snowflake.

Q6

Find the perimeter of the shape at the nth step of the sequence. Take the starting equilateral triangle to have a sidelength of 1 unit.

Q7

Figure it Out

  1. Which of the following are the nets of a cube? First, try to answer by visualisation. Then, you may use cutouts and try.
Q8

A cube has 11 possible net structures in total. In this count, two nets are considered the same if one can be obtained from the other by a rotation or a flip. For example, the following nets are all considered the same —

Find all the 11 nets of a cube.

Q9

Draw a net of a cuboid having sidelengths:

(i) 5 cm, 3 cm, and 1 cm

(ii) 6 cm, 3 cm, and 2 cm

Q10

Observe the front view, top view and side view of the different lines in Fig. 4.6. Is there any relation between their lengths?

Q11

Find the front view, top view and side view of each of the following solids, fixing its orientation with respect to the vertical, horizontal and side planes: cube, cuboid, parallelepiped, cylinder, cone, prism, and pyramid. If needed, see the next problem for clues.

Q12

Match each of the following objects with its projections.

Q13

Draw the top view, front view and the side view of each of the following combinations of identical cubes.

Q14

Imagine eight identical cubes, glued together along faces to form the letter 'C'.

Q15

Which solid corresponds to the given top view, front view, and side view?

Solids to choose from:

Q16

Using identical cubes, make a solid that gives the following projections:

Q17

Find the number of cubes in this stack of identical cubes.

Q18

What are the different shapes the projection of a cube can make under different orientations?

Q19

In addition to the 5 ways shown in Fig. 4.8, are there any additional ways of gluing four cubes together along faces? Can you visualise and draw these as well?

Q20

Draw the following figures on the isometric grid.

[Hint: It may be useful to determine whether the edge to be currently drawn — say, along the height — goes from down to up or up to down. Accordingly, draw the line segment on the grid either in the direction of the height axis or opposite to it.]

Q21

Is there anything strange about the path of this ball? Recreate it on the isometric grid.

[Hint: Consider a portion of this figure that is physically realisable and identify the 3 primary directions.]

Q22

Observe this triangle.

(i) Would it be possible to build a model out of actual cubes? What are the front, top, and side profiles of this impossible triangle? (ii) Recreate this on an isometric grid. (iii) Why does the illusion work?

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