3-Dimensional Figures

3-Dimensional Figures

By Ong Jane

HOW TO VISUALISE RIGHT-ANGLES IN 3D DIAGRAM?

​A plane is a flat, 2D surface that extends infinitely far.

Every face of a 3D diagram is a part of a plane.

A​ line is perpendicular to a plane when it extends directly away from it.

If a line is perpendicular to a plane, it is also perpendiculat to any line in the plane.

Poll

Which line(s) are perpendicular to the shaded face EFGH?

• Line GA

• Line EF

• Line CB

• Line GH

• Line HD

Multiple Select

The diagram shows a prism. Which line(s) are perpendicular to its uniform cross section?

• EN

• EF

• FN

• BC

• AD

Draw

In the diagram, ABCDEFGH is a cube of side 5 cm.

Draw a sketch of Triangle ACG  . Indicate any known lengths and right angles, if any. 

 

Draw

Draw a sketch of triangle ABC. Indicate any known lengths and right angles, if any. 

Draw

Draw a sketch of  Triangle AFC. Indicate any known lengths and right angles, if any. 

 

Draw

The diagram shows a triangular prism.

AE = BE = 5 cm, AB = 6 cm, BC = 9 cm and EN perpendicular to  AB.

Draw a sketch of ADB. Indicate any known lengths and right-angles, if any. 

Draw

The diagram shows a triangular prism.

AE = BE = 5 cm, AB = 6 cm, BC = 9 cm and EN perpendicular to  AB.

Draw a sketch of FEN. Indicate any known lengths and right-angles, if any. 

Draw

The diagram shows a triangular prism.

AE = BE = 5 cm, AB = 6 cm, BC = 9 cm and EN perpendicular to  AB.

Draw a sketch of FNC. Indicate any known lengths and right-angles, if any. 

PROBLEM SOLVING INVOLVING 3-D DIAGRAMS

Some text here about the topic of discussion

​Steps to solving 3D Trigonometry Problems:

1. Visualise a 3-dimentional figure as a composition of triangles or

plane figures in different planes.

​

2. Observe the relationships among various triangles.

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3. Find the necessary unknown sides and angles of the triangles

using the skills previously learnt.