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CURVE TABLES <br />Published by KEUFFEL & ESSER CO. <br />HOW TO .USE CURVE TABLES <br />Table I. contains Tangents and Externals to a 1' curve. Tan. and <br />xt. to any other radius maybe found nearly enough, by dividing the Tan. <br />,fir Ext. opposite the given Central Angle by the given degree of curve. <br />- To find Deg. of Curve, having the Central Angle and Tangent: <br />)ivide Tan. opposite the given Central Angle by the given Tangent. <br />To find Deg. of Curve, having the Central Angle and External: <br />)ivide Ext, opposite the given Central Angle by the given External. <br />To find Nat. Tan. and Nat. Ex. See. for any angle by Table I.: Tan. <br />r Ext. of twice the given angle divided by the radius of a 1° curve will <br />e the Nat. Tan. or Nat. Ex. Sec. <br />EXAMPLE <br />Wanted a Curve with an Ext. of about. 12 ft. Angle <br />of Intersection or L P.=23° 20' to the R. at Station <br />542+72. <br />Ext. in Tab. I opposite 23° 20' =120.87 <br />120.87=12-10.07. Say a 10' Curve. <br />Tan. in Tab. I opp. 23° 20'=1183.1 <br />1183.1=10=118.31. <br />Correction for A. 23° 20' for a 10° Cur. =0.16 <br />118.31-1-0.16 =118.47 =corrected Tangent. <br />(If. corrected Ext. is required find in same way) <br />Ang. 23° 20'=23.33°=10=2.3333=1.. C. <br />2' 19 '=def. -for sta. 542 I. P. =sta. 542+72 <br />4° 4916'= +50 Tan. = 1 . 18.47 <br />7° 19#'= a a " 543 B. C.=sta. 541+53.53 <br />9° 491' = u - " +50 <br />11 ° 40'= u 543+ L. C. = 2 .33.33 <br />86.86 E. C. =Sta. 543+86.86 <br />100-53.53=46.47X3'(def. for 1 ft. of 10° Cur.) =139.41'= <br />2° 19;'=def. for sta. 542. <br />Def. for 50 ft. =2° 30' for a 10* Curve. <br />Def. for 36.86 ft. =1° 50j' for a 10° Curve. <br />