Monthly Archives: October 2011

Estimating Slope Take One

In this silent video I show how a group of Ag and math students estimate slope in order to calculate how erodible the newly planted field will be.   I just wanted the video up fast.  I will spend some more time later refining it and adding some other explanations.

A major question I had as a math teacher, after hearing this is how the Ag class estimates slope at a range management competition.

How is it possible to use the hypotenuse to calculate a fairly accurate estimate?

Finding the Interesection of a Parabola and a Line

Sketch the graphs of the line 2x – y = -2 and the parabola y = -x² – 4x + 1.  Find the coordinates of any points of intersection with technology and with algebra methods.  As student was requesting a video on how to do this, and I couldn’t find one already made online so here goes.

Construction of a Perpendicular Line Through a Given Point and Line

Using a compass and straight edge construct this theorem.   Through a point outside a line, there is exactly one line perpendicular  to the given line.

Construction of a Parallel Line Through a Point

Here is the construction of corresponding angles to create a parallel line through a point and parallel to a given line.