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In. and ieTan. :urve. igent: ent. ternal: ,nal. Tan. ve will CURVE TABLES Published by KEUFFEL & ESSER CO: HOW TO USE CURVE TABLES Table I. contains Tangents and Externals to a 1' curve. T Ext. to any other radius may be found nearly enough, by dividing t or Ext. opposite the given Central Angle by the given degree of _ To find Deg. of Curve, having the Central Angle and Ta Divide Tan. opposite the given Central. Angle by the given Tang = To find Deg. of Curve, having the Central Angle and E: Divide Ext. opposite the given Central Angle by'the given Exte -- To find Nat. Tan. and Nat. Ex. Sec. for any angle by Table --— or Ext. of twice the given angle divided by the radius of a 1' cu --------- -- — be the Nat. Tan. or Nat. Ex. Sec. EXAMPLE Wanted a Curve with an Ext. of about 12 ft. Angle of Intersection or I. P.=23* 20' to the R. at Station 542+72. Ext. in Tab. I opposite 23' 20' =120.87 120.87+12=10.07. Say a 10' Curve. Tan. in Tab. I opp. 23' 20'= 1183.1 1183.1: 10=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'=10=2.3333=L. C. 2'192'=def. for sta. 542 I. P.=sta. 542+72 4-49121 = " +50 Tan. = 1 .18.47 0 1912'= " " «543 53.5 j 9' 49-j"= `< +50 B. C. =sta. -541+53.5,1 11' 40' _ " " " 543+ L. C. = 2 .33.32 86.86 E. C. =Sta. 543+86.8E 100-53.53=46.47X3'(def. for 1 ft. of 10° Cur.) = 139.41'= 20 192' =def. for sta. 542. Def. for 50 ft. =2' 30' for a 10' Curve. Def. for 36.86 ft. =1' 502' for a 10' Curve. sFa "> IAAn9.23°201 N / 10° Curve Y �4y/ x/ \\`� 009% ' In. and ieTan. :urve. igent: ent. ternal: ,nal. Tan. ve will