FB 390 - Laserfiche WebLink

Home Browse Search

DIRECTIONS FOR USE OF TABLES TABLE No. 1. Distance of slope stake from side or shoulder stake for any width roadway, slope 1 r 2 to 1. If ground is nearly level, the cut or fill at side stake is located by the double entry method in left column and top row. The number in body of table in same row and column gives distance from side stake to slope stake. If ground is not level estimate the difference in elevation between the side stake and slope stake, lower target by this amount if cut, elevate if fill. Add this amount to cut or fill and find distance in table. Set up rod at this point, and line of sight should cut target. If it does not make the slight adjustment necessary. TABLE No. 9. To find Tangent and External for curve of any other degree, divide by degree of curve and add correction found in column of corrections. Degree of curve with a given I may be found by dividing tangent, (or external), opposite I by given tangent, (or external). The distance from a point on the tangent to the curve is very nearly the square of the tangent length divided by twice the radius. TABLE II TRIGONOMETRIC FORMULIE. L A= L MOP L B= L PON = L OPL R=OB=c=1 sin A= c=i=a=cosB=LP b b cos A= = =b= sin B=OL e 1 a tan A = MQ = MQ = MQ = cot B = MQ b OM NT NT cot A= =NT= tan B=NT ON= 1 Q sec A= oM = =OQ=cscB=OCR OT OT _ escA= ON 1=OT= see B=OT LMOP vers A = = LM = covers B �$ OP P—LPOP —LP covers A = = OP — LP = vera B OP exsec A = PQ = coexsee B coexsee A = PT = exsee B sin Y2 A = I —Cos A cos Y2 A = 1 +Cos .* 2 2 sin 2A = 2 sin A coF 6 cos 2 A = cos' A — sin' A sin a _ sin B _ sin C, Law of Sines a B C Law of Cosines c' = a'+ 0 — 2 ab cos C Law of Tangents a+b _ tan 1/ (A+B) a—b tan j (A — B)