Page 144 - Math Course 1 (Book 2)

Isometric Views and Cross Sections

Mo. 10

Lesson 8 ref ection symmetry

In three-dimensional space, solids are symmetric
with respect to a plane. This is called ref ection
symmetry.
KEY CONCEPTS:
1. Draw isometric views of three-dimensional A square pyramid has 4 planes of symmetry.
f gures. • Two pass through the altitude and one pair of
2. Investigate cross sections of three- opposite vertices of the base.
dimensional f gures. • Two pass through the altitude and the midpoint
of one pair opposite edges of the base.

MO. 10 - L8a

3D Figures: Isometric Views

and Cross Sections
In a two-dimensional plane, f gures are symmetric
Vocabulary A-Z with respect to a line or a point.

Let us learn some vocabulary
Let’s Begin

corner view (or perspective view)

The view of a geometric solid f gure from a corner Draw a Solid
is called the corner view or perspective view.

You can use isometric dot left Example
paper to draw the corner view
of a solid f gure. Isometric
dot paper is used to draw and A. Sketch a triangular prism 6 units high, with
construct two-dimensional bases that are right triangles with legs 6 units
models of geometric solids and 4 units long.
front right
Step 1
Mark the corner of the solid, then draw segments
cross section 6 units down, 6 units to the left, and 4 units to the
The intersection of the solid and a plane is called a right.
cross section of the solid.

Horizontal Angled
Slice Slice

Vertical
Slice
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