Moving Planes. Slideshow 44, Mathematics Mr Richard Sasaki Room 307. Objectives. Recall names of some common 3d Shapes Understand how moving planes form 3D shapes Understand solids of revolution. Some Simple 3-D Shapes. Cylinder. Cone. Sphere. Square-based pyramid. Hemisphere.
Slideshow 44, Mathematics
Mr Richard Sasaki
Recall names of some common 3d Shapes
Understand how moving planes form 3D shapes
Understand solids of revolution
A plane is a flat 2D surface thought to be infinite in length.
If a finite plane moves rapidly, it can create the form of a 3D object. Similarly, if we trace the movement of the object it can do the same.
What is a plane?
A coin is lifted up and down rapidly covering a height of 5cm. If the centre of the coin remains as the centre of the base of the 3D shape, state the shape produced and draw it.
Lateral surface – All of the surface except for the base(s)
A prism with bases congruent to the initial polygon
Legs are two of the edges of a right-angled triangle.
What is a leg?
Note: Leg is only used with right-angled triangles. Not with other triangles.
An apex is thought of as the sharpest point of a shape. It’s often at the top (like a peak).
What is an apex?
Shapes like these are most commonly associated with “apex”.
solid of revolution
We call this a .
In Question 1 on the last worksheet, we had an example where a 3D shape is produced by spinning a polygon about an edge of it.
We will think of a solid of revolution has being based around its vertical centre.
Let’s try to think about other shapes!
If we connect a semi-circle to the central line of revolution, what shape will appear?
The distance from the central line of revolution must be the same horizontally about every part of the solid.