CROSS-SECTION- THE SHAPE YOU GET WHEN CUTTING STRAIGHT ACROSS AN OBJECT PARALLEL- LINES IN A PLANE THAT DO NOT MEET PERPENDICULAR- RELATIONSHIP BETWEEN TWO LINES WHICH MEET AT A RIGHT ANGLE FACE- FLAT PLANAR SURFACE EDGE- LINE WHERE TWO SURFACES MEET VERTEX- CORNER OF AN INTERSECTION BASE- SIDE OF A PLANE FIGURE OR FACE OF A SOLID ANGLE- FIGURE FORMED BY TWO RAYS OR LINE SEGMENTS DIAGONAL- CROSSING FROM ONE CORNER TO ANOTHER PLANE- FLAT TWO-DIMENSIONAL SURFACE RECTANGULAR PRISM- A 3D SHAPE THAT HAS 6 FACES, 8 VERTICES, AND 12 EDGES RIGHT SQUARE PYRAMID- A 3D SHAPE THAT HAS 5 FACES, 5 VERTICES, AND 8 EDGES Vocabulary
In this lesson you will learn how to describe the cross sections of a rectangular prism by slicing at different angles. Lesson A
Review Rectangular Prism Six Faces Meet at 90˚ Plane Infinitely Long Infinitely Tall 3D 2D
Interpreting a Perspective Drawing Looking at the prism straight on, the top face looks like a parallelogram. When the top face is straight up, you can see that it is actually a rectangle.
A Cross Section is the two-dimensional shape you get when you cut a three- dimensional shape with a plane. The Plane can be perpendicular or parallel. Perpendicular Planes intersect to form right angles. Parallel Planes never intersect
Cutting a rectangular prism parallel to its base: The blue part is your Cross Section
Cutting a rectangular prism NOT parallel to its base: The blue part is your Cross Section
Cutting a rectangular prism perpendicular to its base: The blue part is your Cross Section
Lesson B In this lesson you will learn how to describe the cross sections of a right square pyramid by slicing at different angles.
Review Vertex 5 Faces From Lesson A, recall what a plane is and how it relates to cross sections. View slide five for reference. Right Square Pyramid
Cutting a right pyramid with a plane parallel to its base: The blue part is your Cross Section
Cutting a right square pyramid NOT parallel to its base: The ends on the quadrilateral are different lengths because the far side is closer to the top vertex. The blue part is your Cross Section
Cutting a right square pyramid with a plane perpendicular to its base containing the vertex: