# Math Is Like…Hard?

*By Eric Dykstra On May 1, 2008 · 11 Comments · In Amazon, Books, Woodworking*

Remember that time you asked your algebra teacher when you’d ever need to solve for X in real life? There’s a good chance you still haven’t found a use for your higher math skills, but Toolmongers will likely encounter plenty of practical math issues during a project. This handy book’ll show you how to calculate roof pitch, lay out stairs, make sense of a scientific calculator, and lots of other stuff.

The guide contains 256 pages of facts, figures, and conversion tables aimed at industry, construction, and home projects. The book outlines simple projects that allow you to apply your newfound math skills using basic materials. It also includes reviews and testing material to keep you sharp. It measures 10.6″ x 8.7″ x 0.4″ with precut holes, so you can keep it in a three-ring binder out in the shop for easy reference.

All this knowledge will run you about $20.

Chenier’s Practical Math Application Guide [Official Site]

Street Pricing [Google Products]

Via Amazon [What’s This?] (ISDN: 096260612X) [What’s This?]

This might come in handy. Since I went through all the higher math, I can’t remember how to do basic math.

I use a construction calculator.

http://www.calculated.com/cat4/Construction+Calculators.html

I didn’t make it this far into the future for nothing, still waiting for my flying car and robot servant though.

Still probably a good idea to know the math.

Trig comes in handy many time when the calculator will not.

You can get a pretty good estimate of a tree’s height via some simple triangulation. It sure beats climbing – and gives you a perspective before felling.

Re:

fred Says:

May 1st, 2008 at 3:18 pm

Trig comes in handy many time when the calculator will not.

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You can get trig functions in a construction calculator.

http://www.calculated.com/4/prd102/Construction+Master+Pro+Trig.html

My construction calculator works fine – but setting up the “problem” so you can accurately estimate tree heights with no buildings as frames of reference takes knowing the underlying geometry and trigonometry. The same is true for using a transit to calculate distance. The Romans, great engineers that they were could calculate the width of a river without the need to cross it – just using some simple triangulation.

Re;

Fred Says:

My construction calculator works fine…

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There is something to be said for knowing the math. But there is also something to be said for doing it the gadget freaks way.

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but setting up the “problem” so you can accurately estimate tree heights with no buildings as frames of reference takes knowing the underlying geometry and trigonometry.

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All it takes is whipping out a laser rangefinder.

Re: Fred says

but setting up the “problem” so you can accurately estimate tree heights with no buildings as frames

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Old loggers trick of using a stick to measure treefall illustrated in link – under tree height measurement.

ww w.americanforests.org/resources/bigtrees/measure.php

if your going to do it often get yourself a “cruisers stick”

ww w.forestry-suppliers.com/product_pages/View_Catalog_Page.asp?mi=1441#

Moderation bots suck

add http followed by :// and then take the space out from between ww w.

The stick (or even pencil) method for estimating heights actually relies on the concept of similar triangles.

Try using a laser rangefinder on a bushy blue spruce on a sunny day and see what you get for accuracy.

Why don’t you just cut the tree down and measure it on the ground with a tape measure. It may seem like overkill, but I bet you will get a pretty accurate number.

Re;

Fred said:

Try using a laser rangefinder on a bushy blue spruce on a sunny day and see what you get for accuracy.

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My educated eye is usually good for +/- 6′ (I’ve been dropping trees for 25 years)

Bosch DLR165K is good for less than an inch if I can get a good spot.

Leica CRF 900 is accurate +/- 3 ft [usually spot on] on trees over 30ft.

and if I want to get silly.

ww w.leica-geosystems.com/corporate/en/ndef/lgs_5574.htm

It’s the wind that makes it fun.

Just as easy to climb the spruce and top it, to be sure it fits in the fall zone.

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Re:

Scraper Says:

Why don’t you just cut the tree down and measure it on the ground with a tape measure. It may seem like overkill, but I bet you will get a pretty accurate number.

heard a joke about that once

Two blonde guys were standing at the base of a flagpole, looking up. A woman walked by and asked them what they were doing. “We’re supposed to measure the height of this flagpole,” said blonde guy number one, “but we don’t have a ladder.” The woman took a wrench from her purse and loosened some bolts. The guys helped her lay down the flagpole. Then the woman got a tape measure from her pocket, took a measurement and said, “Eighteen feet, six inches,” and walked away. Blonde guy number two shook his head and laughed. “Isn’t that just like a girl? We ask for the height and she gives us the length!”

I have my physics students do some triangulation every year to determine the distance between two points without a direct measure. Usually the distance across a field or something similar. One restriction is a “dead line” they can’t cross to get closer to the other point. We use transits made from pieces of 1×12, rulers, three pencils or sharpened pieces of dowel. Most results are off by less than 5% and almost all are within 7%. With some practice, many get within 3%.