This is NOT an answer to the gentleman's question about walking
the length of his lot, but might be handy for some who need to
quickly solve a simple equation. I'll use the real estate version
of it for the example, but it is just as handy for Ohm's Law or
any other simple equation.
In Real Estate appraisal, there is a very simple equation where
the (V)alue of a property equals its (I)ncome / capitalization
That can be expressed as V=I/R I=R*V or R=I/V Many of the
appraisal folk are not that skilled in even the simplest algebra,
so they need tools to help them convert between Income, Value and
the cap Rate. To do this, we teach them "IRV." Hopefully, this
will appear correctly on your screen. If not, just follow the
Draw a circle on a piece of paper and then draw a horizontal line
across the circle from the 9:00 position to the 3:00 position.
Then, draw a vertical line from the center of the circle to the
6:00 position. In the top half of the circle, write I. In the
lower left quadrant, write R and the lower right quadrant gets a
V. To solve for any variable, merely cover the item up with your
finger. Covering R, for instance, you have I/V remaining.
Covering V, you have I/R and finally, by covering I you have R and
For Ohm's law E= I*R (Voltage = Current *
Therefore E goes in the upper half of the circle, with I and R
occupying the two bottom quadrants. Covering E with your finger
gives you I and R to multiply. Covering R, you have E/I and
finally covering I gives you E/R. This also works, obviously with
P= E*I (Power = Voltage *
Suppose you were an idiot.
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