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FIELD BOOK 538 g" <br /> - <br /> CURVE TABLES. <br /> -- -- Published by KEUFFEL & ESSER CO. <br /> - --- HOW TO USE CURVE TABLES. <br /> Table I. contains Tangents and Externals to a 10 curve. Tan.and <br /> -- t,to any other radius maybe found nearly enough,by dividing theTan. <br /> r 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 /> vide Tan.opposite the given Central Angle by the given Tangent. <br /> --- - To find Deg. of Curve, having the Central Angle and External: <br /> vide Ext. opposite the given Central Angle by the given External. <br /> ----- __ __ To find Nat.Tan.#nd Nat.Ex.See.for any angle bq Table L:Tan. <br /> -- 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. <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. 1 <br /> Ext.in Tab. I opposite 230 20'=120.87 <br /> - - 120.87-i-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.=0.18 <br /> ---- -— - - -- 118.31+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=L.C. <br /> - - -- 2°191'=def.for sta. 542 I.P.=sta. 542+72 <br /> _.__--- 4°49}' +50 Tan.= 1 .18.47 <br /> - 7°19j'= « u u 543 <br /> 9049j'= u u u +50B. C.=sta_ 541+53.53 <br /> - --- - 11°40'= a . ." 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 /> - 20 19J'=def.for sta.542. <br /> Def.for 50 ft.=2°30'for a 10°Curve. <br /> s z° ,,Def.for 36.86 ft.=1°50}'fora 10°Curve <br /> -' - - <br /> h7 5,0 <br /> W Curr. <br /> 1 <br />