DO NOW! Only things on desk: Work silently & independently Pencil Handouts you picked up Work silently & independently

To meet, touch, go/cut through, cross, etc. DO NOW!: Fill in the blank with always, sometimes, or never. If two planes intersect, then they intersect at a line. If two lines intersect, then they intersect at two different points. 𝐴𝐵 is another name for 𝐵𝐴 . Two lines intersect at one point. One line can be drawn through three points. In your own words, what does intersect mean? always never always sometimes sometimes To meet, touch, go/cut through, cross, etc.

no no yes at point M Yes at point R no 7. Will 𝐽𝑀 and 𝐿𝑄 ever intersect in space? (Lines that intersect on the page do not necessarily intersect in space.) no 8. Will the following pairs of lines intersect in space? 𝐽𝐾 and 𝑁𝑅 𝐿𝑀 and 𝑀𝑅 𝑀𝑅 and 𝑄𝑅 𝐾𝐿 and 𝑁𝑄 no yes at point M Yes at point R no

9. Are the following pairs of lines coplanar?  This means: 𝐽𝐾 and 𝑅𝑄 𝐽𝑁 and 𝐿𝑅 𝑄𝑅 and 𝑀𝑅 𝐽𝐿 and 𝑁𝑄 Can they lie in the same plane?

We will be able to: - Name and describe the 4 different types of lines

2 Lines Oblique Intersecting Perpendicular Parallel Non-Intersecting are described as… Oblique Intersecting Perpendicular Parallel Non-Intersecting Skew

Think about which are coplanar and which are not With your group, use the provided examples & non-examples to complete the table. Type of Lines Characteristics Picture   OBLIQUE PERPENDICULAR SYMBOL: PARALLEL SKEW Think about which are coplanar and which are not

Intersecting Oblique Lines Intersect to form acute or obtuse angles

“Look for the box in a picture! is perpendicular to line l” Perpendicular Lines Intersect to form a right angle Symbol: Example: j l l j “Line j is perpendicular to line l”

“Look for the double arrow in a picture! Parallel Lines A B m n C D AB is parallel to CD NEVER intersect Coplanar Symbol: Example: AB CD “Line AB is parallel to line CD”

Skew Lines NEVER intersect Non-Coplanar m and n are skew B m n C D m and n are skew NEVER intersect Non-Coplanar a and b are skew

Example 1: Think of the sides in the figure as planes. List all lines parallel to 𝐶𝐷 . List all lines parallel to 𝐶𝐷 containing point A. List all lines skew to 𝐶𝐷 . List all lines skew to 𝐶𝐷 containing point A. List all lines perpendicular to 𝐶𝐷 . List all lines perpendicular to 𝐶𝐷 containing point A. Extension: Name the plane that is parallel to Plane EFG.

Example 2: YOUR TURN! List all lines parallel to 𝐸𝐻 . 𝑭𝑮 , 𝑫𝑨 List all lines parallel to 𝐸𝐻 containing point F. List all lines skew to 𝐸𝐻 . List all lines skew to 𝐸𝐻 containing point F. List all lines perpendicular to 𝐸𝐻 . List all lines perpendicular to 𝐸𝐻 containing point F. Extension: Name the plane that is parallel to Plane BAH. 𝑭𝑮 , 𝑫𝑨 𝑭𝑮 𝑭𝑪 , 𝑩𝑮 , 𝑨𝑮 , 𝑫𝑪 , 𝑩𝑨 𝑭𝑪 𝑭𝑬 , 𝑯𝑮 , 𝑬𝑫 , 𝑨𝑯 , 𝑭𝑬 Plane CDE

Example 3: Think of the sides of a figure as planes. List all lines parallel to 𝐾𝑁 . List all lines skew to 𝐽𝑀 . c) Describe 𝐽𝐾 and 𝑁𝐿 . 𝑱𝑴 and 𝑯𝑳 𝑲𝑯 and 𝑵𝑳 𝒔𝒌𝒆𝒘

What is the best description of the horizontal bars in the photo? INTERSECTING PERPENDICULAR SKEW PARALLEL 𝐎

Is the platform perpendicular, parallel, or skew to the ground? 𝐩𝐚𝐫𝐚𝐥𝐥𝐞𝐥

Is the arm perpendicular, parallel, or skew to a telephone pole? 𝐬𝐤𝐞𝐰