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s <br />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 />�'. <br />_ <br />Ext. to any other radius may be found nearly enough, bydividing the Tan. <br />d <br />ft } or Ext. opposite the given Central Angle by the given degree of curve. <br />1A. To find Deg. of Curve, having the Central Angle and. Tangent: <br />+s, i' , ` Pivide Tan. opposite the given Central Angle by the given Tangent., <br />( <br />I. To find Deg. of Curve, having the Central Angle and External: <br />.!f Divide Ext. opposite the given Central Angle by the given External. <br />r <br />ul <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 1° curve will <br />I be the Nat. Tan. or Nat. Ex. Sec. <br />t <br />EXAMPLE <br />" <br />Wanted a Curve with an Fxt. of about 12 ft. Angle <br />of Intersection or 1. P.=230 20' to the R. at Station <br />542-72. <br />Fxt. in Tab. I opposite 23° 20'=120.87 <br />` <br />" <br />I 120.87=12=10.07. Say a 10° Curve. <br />t <br />k Tan. in Tab. I opp. 23° 20'-1183.1 <br />1183.1=10 =118.31. <br />1 <br />I Correction for A. 23` 20' for a 10° Cur. <br />118.31 +0.16 =118.47 =corrected Tangent. <br />I y •_ <br />; , ,. <br />I <br />n:•:'' <br />(If corrected Ext. is required find in same way) <br />Ang. 23° 20'-23.33 -10=2.3333=1.. C. <br />I <br />E <br />2° 19,'=def. for sta. 542 1. P. = eta. 542+72 <br />4° 492 _ " " r` +50 Tan. = 1.15.47 <br />j <br />7° 191.: = a u a x543 <br />9040 ra r' ° +50 B. C.=sta. 541+53.53 <br />11° 40'= u µ ° 543+ L. C. = 2 .33.33 <br />86.86 F. C. =Sta. 543 x-86.86 <br />100-53.53-46,47x31(def. for 1 ft. of 10° Cut.) =139.41= <br />2° 192' =.def. for sta. 542. <br />Def. for 50 ft. =2° 30' for a 10° Curve. <br />x <br />Def. for 36.86 ft. =1° 54;' fora 10° Curve. <br />s <br />