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ji CURVE TABLES Published by KEUFFEL & ESSER CO. - - - --- HOW TO USE CURVE TABLES — Table I. contains Tangents and Externals to a I' curve. Ta t. to any other radius may be found nearly enough, by dividing tl r Ext. opposite the given Central Angle by the given degree of i To find Deg. of Curve, having the Central.. Angle and Tar ivide Tan. opposite the given Central Angle by the given Tang, To find Deg. of Curve," having the Central Angle and Ex ivide Eat. opposite the given Central Angle by the given Extei To find Nat -Tan. and Nat. Ex. Sec. for any angle by Table I r Ext. of twice the given angle divided by the radius of a 1' cur e the Nat. Tan. or Nat. Ex. Sec. - -- — - 1 j EXAMPLE -- ,—f Wanted a Curve with an Ext. of about 12 ft. Angle of Intersection or 1. -P. -230 20' to the R. at Station 542+72. / Ext. in Tab. I opposite 2311 20'= 120.87 120.87+12=10.07. Say a 10° Curve. Tan. in Tab. 1 opp. 23° 20'=1183.1 1183.1T10=118.31.' __ Correction for A. 23° 20' for a 10° Cur.=0.16 118.31+0.16 =118.47 =corrected Tangent. (If corrected Ext. is required find in same way) Ang. 23° 20'=23.33°110=2.3333=L. C. — - i 2° 19',- = def. for sta.. 542 L P. = sta. 542+72 4° 49" = °' ' +50 Tan. = 1 =. 18:47 —' `i 7° 19'= " " " 543 S. C. =sta. 541+53-52 2 53.53 .9 ° 49j' = " " " +50 = 11° 40' = u " " 543-F C. Z .33.33 86.86 E. C.=Sta. 543+86.8( ! 100-53.53=46.47X3'(def. for 1, ft. of 10° Cur.) =139.41' = 2° 1.9E=def. for sta. 542. . ' Def. for 50 ft. =2° 30' for a 10° Curve. - Def. for 36.86 ft. =11 50#' for a 10° Curve. I.P.An9.Z3•Z0' -. P� 9T i 10•Ci{y`VO n. and [eTan. ,urve. gent: int. tern al: nal. .: Tan. ve will