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_J CURVE TABLES <br />Published by KEUFFEL & ESSER CO. <br />HOW TO USE EURVE TABLES <br />! <br />' <br />L ` <br />li <br />-Table I. contains Tangents grid Externals to a 1° cuive. Tan. and <br />Ext. to any other radius may be f ound nearly enough, by dividing the Tan. <br />oi: 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 />Divide Tan., opposite the given Central Angle b'y'the given Tangent. <br />To find -De of Curve, havingthe :Central An le and External: <br />Divide Ext. opposite the given Central Angle by the given External. <br />To find Nat. Tan. and Nat. Ex. Sec. for any angle by.Table I.: Tan. <br />or. Ext. of twice the given angle divided by the,radius of a, t° curve will <br />be. the Nat..Tan. or Nat. Ex. Sec. ' <br />' <br />+I ' �/ <br />{Il <br />a, <br />I <br />f.: EXAMPLE `.:. ,.. <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 <br />•542+72. <br />Ext. in Tab. I o pposite 23° 20'= 120.87 <br />/� <br />120.87 =12 =10.01. Say a 10° Curve. <br />Tan. in Tab. I opp. 23° 20'= 1183.1 <br />!i <br />J' <br />? <br />p 1183.1=10=118.31. 4 <br />Correction for A. 23° 20' for a 10° Cur: =0.16 '. . <br />118.31+0.16=118.47=corrected Tangent... . <br />(If, corrected Ext: is required find in same way) <br />p "�( Ang. 23° 20'=23.33°=10=2.3333 L. C. <br />0 <br />' f`5 2° 191 <br />20 for sta. 542_. I. P. . sta. 542 F72 <br />�3 <br />4° 492 _ :.. -1-50 :Tan. = T .-18.471 <br />11 <br />! <br />E : <br />7°•192'= ;" 543. B. C.=sta. - 541+53.63 <br />p = « .. 53.53 `. <br />g 0 . 7 9° 49 1 , x-50 <br />2 L. C. = 2 .33.33 <br />54 <br />11° 40' _ u « . 3+{ <br />q j <br />, / / <br />86'.86 E. C.=Sta. 543+86.86 <br />100.-53.53=46.47X3'(def. for•l ft. of 10° Cur.)=139:41'= <br />KJ <br />0 2° 192'=def.'for sta. 542. <br />Def. for 50 ft.=2° 30' for a 10' Curve. <br />Def. for 36.86 ft. =1° 501' for a 10° Curve. <br />LkAn'.23°20' .- ... <br />fir/ <br />r <br />i� 1. <br />to*curve <br />