SECTION 1.4SECTION 1.4SKETCHING INTERSECTIONSSKETCHING INTERSECTIONS

LEARNING TARGETS:1.Students will be able to sketch simple figures and their intersections.

VOCBAULARY1. Intersection

Activity 1.4 – Exploring Intersections Question:

When planes meet, what points do they intersect?

Materials: Three index cards Scissors Pencil

Page 21 in Textbook

Step 1:

Label two index cards as shown. Cut each card along the dotted line.

Step 2:

Slide two cards together. Answer Exercises #1-4.

Step 3:

Label and cut a third card as shown. Cut another slot in plan M and slide the cards together.

Answer Exercises #5-7.

What does an Intersection Look Like?

The photograph shows the intersection of two streets in Seattle. The intersection is the part where the two streets cross each other.

In geometry, figures intersect if they have any points in common.

The intersection of two or more figures is the point or points that the figures have in common.

Postulate 3: Intersection of Two Lines

If two lines intersect, then their

intersection is a point.

Postulate 4: Intersection of Two Planes

If two planes intersect, then their intersection is a

line.

Quick Thought:

Example 1: (Textbook)

EXAMPLE: (In Notes)

Name the intersection of FJ and KM Name the intersection of NH and KM Name the intersection of NP and FJ

Example 2: (Textbook)

Example: (In Notes)

Sketch Intersections of Lines and Planes

Sketch a line that does not intersect with a plane.

SOLUTION:

Sketch a plane and a line that is in the plane.

SOLUTION:

Sketch Intersections of Lines and Planes

Sketch a plane and a line that intersects the plane at one point.

SOLUTION:

Sketch Intersections of Lines and Planes

Sketch 2 planes that intersect in a line. SOLUTION:

Sketch Intersections of Lines and Planes

Daily Puzzler

How many distinct (different) planes can intersect at a single line m?

HOMEWORKSection 1.4 AssignmentPage 25 #8-20 EVEN, 22-32 ALL, 34–54 EVEN

Due Tuesday, 10/04