Johnegee are you working with degrees or radians?
If you use the sine or cosine functions in Excel, for example, it assumes that you’re using radian measure. (A radian is the length of a circle’s radius traced along its circumference: just like a quarter circle is 90 degrees, it’s pi/2 or about 1.57 radians).
You could use trig or pythagurus, but the simplest method seems to be using RATIOS.
If you are 1/4 the way along (from the low end), you must be 1/4 the way up …
Ah yes if you do not already know the hypotenuse total length, you’d need to calculate that…
When calculating the ratio of ‘how far along’. or ‘how far up’, you can any side in the ratio
eg the horizontal , hypotenuse or height… but make sure to use the correct - matching, respective - total length .
eg If 1/4 away along the x, then 1/4 higher, and 1/4 the way up the hypotenuse… you see ?
Sorry, I can’t visualize the problem. If you’re measuring along the bottom of the plywood sheet, how is it possible to have the tape move away from the edge without being noticed?
Hector St Clare and pulykamell, that’s it. Radians versus degrees. The Excel formulas I’m now using, thanks to your help, are accurate to several decimal places beyond all practical reason.
one leg length = Hypotenuse * COS(RADIANS(known angle))
other leg length = Hypotenuse * SIN(RADIANS(known angle))
Is there a more elegant way than the above?
kaylasdad99, in real life as opposed to the idealized example I used, one rarely tries to line up the tape measure with the exact bottom of the sheet, because that would take too long or require a second person to position what’s called the dumb end of the tape. No, instead you just place your hook over one end somewhere near the bottom of the sheet and you adjust the smart end of the tape up or down to make it look parallel to the bottom, and then you make your crow’s-foot mark on the sheet at the designated place on the tape.
If you do that again at the top of the sheet and connect your two crow’s-feet with a chalk line, you’ll have a straight line at the distance you want so you can squarely cut the sheet into two rectangles. (A lone carpenter with a little training who’s done it for a living for a day can perform this entire process, including making the cut with a circular saw, in less than a minute. No kidding.)
Some anal-retentive novices spend way too much time adjusting the tape so it’s EXACTLY parallel to the bottom, whereas experts have learned it makes little difference. Indeed, EXACTLY how little difference is what I was hoping to learn from SD members, given the three factors. (And I want to thank you all again.)
For example, if your tape is a whopping 3 inches high at the right end over a distance of only 48 inches, your mark at 32 inches on the tape will still be short by less than 1/16th of an inch, which is easily within tolerances for 99% of rough framing. Factors such as the width of your pencil, where you press that pencil against the sheet relative to the tape to make your vertex marks, and simple misplacement of the saw blade kerf relative to the cut line can overwhelm any error made by raising one’s tape a little, even if one DOES notice it.