3D Figures and Their Properties

Mr. Sia's lesson covers 3D figures, including polyhedrons, prisms, cylinders, cones, and spheres. It explains how to create nets for these figures and explores cross sections, demonstrating how slicing a solid with a plane results in different shapes. The lesson also discusses how rotating 2D shapes like rectangles and triangles can form 3D objects such as cylinders and cones.

What is a polyhedron?

• A three-dimensional figure with polygonal surfaces

• A two-dimensional shape with curved surfaces

• A figure with no edges

• A shape with only circular bases

Which of the following is true about a prism?

• It has two parallel and congruent polygonal bases

• It has only one base

• It is always a cube

• Its sides are all triangles

What is a net in the context of 3D figures?

• A tool for measuring angles

• A type of polygon

• A 2D diagram that can be folded into a 3D figure

• A 3D model of a figure

What shape is formed by a cross section of a cone parallel to its base?

• Triangle

• Hexagon

• Circle

• Square

If a cross section of a hexagonal prism is perpendicular to its base, what shape might it be?

• Circle

• Triangle

• Rectangle

• Hexagon

What shape is a cross section of a rectangular prism if the plane is parallel to one of its faces?

• Triangle

• Rectangle

• Circle

• Pentagon

How does a square relate to a rectangle in terms of cross sections?

• A square is not a rectangle

• A square is a type of rectangle

• A square is larger than a rectangle

• A square has more sides than a rectangle

What 3D shape is formed by rotating a rectangle around one of its sides?

• Sphere

• Cone

• Pyramid

• Cylinder

What 3D shape is formed by rotating a right triangle around one of its legs?

• Sphere

• Cube

• Cone

• Cylinder

Which of the following is NOT a 3D figure discussed in the lesson?

• Sphere

• Pyramid

• Ellipse

• Cylinder