Geologic features such as the slope of a plane that are not true can appear shallower than meets the eye. To prove this you need to calculate the apparent dip of the plane that is oblique to its strike. The strike is the horizontal direction of the plane. This is done by using a section of the plane that is parallel to its strike. You will require the use of a diagram for the calculation.

- Skill level:
- Moderate

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### Things you need

- Graph paper
- Protractor

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## Instructions

- 1
Determine the scale used for the calculation such as inches or feet. Make a note of the contour interval to use for the scale, such as 50 feet. Make a note of the interval, such as two squares equal 50 feet on a piece of graph paper.

- 2
Draw a vertical line that intersects a horizontal line on a sheet of graph paper. Label the horizontal line "x" and the vertical line "y."

- 3
Draw a 45-degree line from the intersection of line "x" and line "y" outward to the right.

- 4
Make a mark on line "y" to indicate points for "100," "200," and "300." Make a dot that is in-between the "100" and "200" marks of line "y" on the diagram. Label this dot "160 feet."

- 5
Count two squares below line "y" and make a mark for "-100." Count two additional squares and make a mark for "-200."

- 6
Count three squares to the left of line "x" and make a mark. Count an additional three squares and make a second mark. Draw a line from the second mark on line "x" to the mark for "-200" on line "y."

- 7
Determine the angle of the line you just drew with the protractor. This result is the apparent dip for the plane.