Unfolding three Dimensional Figures Worksheet

**Page 1**

1.

Find the number of triangles you would need in a net to make a triangular prism.

a. | 6 | ||

b. | 2 | ||

c. | 4 | ||

d. | 3 |

So, the number of triangles in the net to form a triangular prism is 2.

Correct answer : (2)

2.

Pick a net you could use to make a cone of radius 3 inches.

a. | Net 1 | ||

b. | Net 2 | ||

c. | Net 3 | ||

d. | None of the above |

The circumference of the circular base = 2

= 2 x

[Substitute

= 6

[Multiply 2 and 3.]

In nets (2) and (3), the length of the arc = 6

To form a cone, the circumference of the circle must equal the length of the arc and the circle should be adjacent to the arc.

In net (3), the length of the arc, 6

So, only net (2) can be used to form a cone.

Correct answer : (2)

3.

Identify the solid that can be formed by the net.

a. | pyramid | ||

b. | square pyramid | ||

c. | triangular pyramid | ||

d. | triangular prism |

A triangular prism has two triangular bases and three rectangular faces. So, the above figure cannot be a triangular prism.

A square pyramid has one square base and four triangular faces. So, the above figure is not a square pyramid.

A pyramid has triangular faces that meet at one point and a base that is a polygon. So, the above figure cannot be a pyramid.

When the above net is folded we get a triangular pyramid.

Correct answer : (3)

4.

Name the three dimensional figure that can be formed from the net.

a. | cube | ||

b. | cone | ||

c. | sphere | ||

d. | cylinder |

A cone has one vertex and one circular base.

A cube has six square faces.

A sphere is the set of all points that are the same distance from a given point, called the center.

So, only a cylinder can be formed from the net.

Correct answer : (4)

5.

Which of the following figures represents a cone?

a. | Figure 2 | ||

b. | Figure 4 | ||

c. | Figure 3 | ||

d. | Figure 1 |

Correct answer : (2)

6.

Choose the figure which matches the following net.

a. | figure 1 | ||

b. | figure 4 | ||

c. | figure 3 | ||

d. | figure 2 |

So, figure 2 is the correct choice.

Correct answer : (4)

7.

Name the three dimensional figure that can be formed from the net.

a. | Triangular prism | ||

b. | Cube | ||

c. | Sphere | ||

d. | Square pyramid |

The six equal squares form six square faces when folded.

A square pyramid has four triangular faces and a triangular prism has two triangular bases.

A cube has six congruent square faces.

So, only a cube can be formed from the net.

Correct answer : (2)

8.

Which of the nets can be folded to form a triangular pyramid?

a. | All the above | ||

b. | Figure 3 | ||

c. | Figure 1 | ||

d. | Figure 2 |

Among the figures, figure (3) has four triangles.

Figures (1) and (2) have squares in their nets, which are not required for a triangular pyramid.

So, only figure (3) can be folded to form a triangular pyramid.

Correct answer : (2)

9.

Which of the nets can be folded to form a triangular prism?

a. | Figure 3 | ||

b. | Figure 1 | ||

c. | All the above | ||

d. | Figure 2 |

On folding figure 1, boxes 1 and 5 form the triangular faces and the boxes 2, 3, and 4 form the lateral faces.

So, figure 1 forms a triangular prism.

On folding figure 2, boxes 1 and 2 form the triangular faces and the boxes 3, 4, and 5 form the lateral faces.

So figure 2 forms a triangular prism.

On folding figure 3, boxes 1 and 2 form the triangular faces and the boxes 3, 4, and 5 form the lateral faces.

So, figure 3 forms a triangular prism.

All the figures form a triangular prism. So choice-D is the correct answer.

Correct answer : (3)

10.

What is the name of the three-dimensional figure which can be formed from the net in the figure?

a. | No three dimensional figure can be found | ||

b. | Cone | ||

c. | Triangular pyramid | ||

d. | Cylinder |

The three-dimensional figure with one circular base and one vertex is called as cone.

So, a cone can be formed from the net in the figure.

Correct answer : (2)