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33 - -- CURVE TABLES. <br /> ----------- ----.--- .cb 2�1/. Published by KEUFFEL & ESSER CO. <br /> HOW TO USE CURVE'TABLES. <br /> Table I. contains Tangents and Externals to a V curve. Tan.and <br /> Ext.to any other radius maybe found nearly enough,bydividing theTan. <br /> or Ext.opposite the given Central An le by the given degree of curve. <br /> - - To find Deg. of Curve havingthe <br /> Divide Tan. o Cggentral Angle and Tangent: <br /> entral <br /> _. <br /> To find Deg. f Curve,eh ving thenCenle taltAnhe gle and iven aExte nal: <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 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. <br /> Ext.in Tab. I opposite 231 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+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°19j'=def.for sta. 542 I. P.=sta. 542+72 <br /> { 404911= it u 1, <br /> +50 Tan.= 1 .18.47 <br /> - - 70 191,= u a u <br /> 904951t= n a a -15-50 B. C.=sta. 541+53.53 <br /> 11°40'= 11 a 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 /> - - ------ -- ------ --------- - -- 20 191'=def.for sta.542. <br /> Def,for 50 ft.=2°30'for a 10°Curve. <br /> ---- - - --- --- --- — --- Def.for 36.86 ft.=10 5011 for a 10°Curve. <br /> LP.An9.23°20 <br /> U <br /> 10°Curve <br /> �\ <br /> 44"/ <br /> , . lk <br />