Intersection of Two Planes: / and /
A Visible Geology Tutorial

Measure
To the strike:
Tick
Use a pencil!
Rotate
Align N-S
Measure
From the right. Dip:
Trace
Draw a great circle.
Rotate
Back to correct orientation.
Erase
Did you use a pencil?
Pick
The line of intersection.
Rotate
Align E-W
Measure
The plunge is:
Rotate
Back to correct orientation.
Measure
The trend is:
Visualize
Two planes.
Visualize
One Line: /
Remember
It should be fun!