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CURVE TABLES. <br />Published by KEUFFEL & ESSER CO. <br />HOW TO USE CURVE 'TABLES. ® �' <br />X=1Po k <br />Table I. contains"Tangents and Externals to a 1° curve. Tan. and Ila- <br />Ext. <br />laExt. to any otb er radius maybe found nearly enc ugh, by dividing the Tan. <br />or Ext. opposite the given Central Angle by tb a given degree of curve. <br />To find Deg. of Curve, having the Central Angle and Tangent: <br />Divide Tan. opposite the given Central Angle by the given Tangent. <br />To find Deg. of Curve, having the Cent¢,al Angle and External: <br />Divide 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 />or Ext. of twice the given angle divided by the radius of a 1° curve will <br />be the Nat: Tan. or Nat. Ex. Sec. <br />EXAMPLE. Zg� <br />Wanted a Curve with an Ext. of about 12 ft. Angle <br />of Intersection or I. P.=23* 20' to the R. at Station �9 3 <br />542+72. <br />Ext. in Tab. I o�� <br />pposite 23° 201 =120.87 <br />120.87--12=1.0.07. Say a 10" Curve. <br />Tan. in Tab. I opp. 23' 20' =1.183.1 <br />1183.1=10 =118.31. <br />Correction for A. 23' 20' for a 10° Cur. =0.16 <br />118.31 +0.16 =118.47 = corrected '.Tangent. <br />(if 'corrected Est. is required find: in same way) <br />Ann. 23'20'=23.33 =10=2.33 c3 =L. C. <br />2° 192'=def, for sta. 542 I. P. =sta.. 542+72 t <br />4' 49i'=* +50 "fan. = 1 .18.47 <br />70192 = a a a 543 <br />i= a a a B. C.=sta. 541+53.53 <br />9o i 492+50 <br />110 40'= °f " « 53+. L. C. = 2 .33.33 <br />86.96 E. C. = St a. 543+86.86 r <br />100-53.53=46.47X3'(def. for 1 ft. of 10°'Cur.)=139.41'= b� <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° 502' for a 1+0' Curve. <br />S4 <br />r <br />