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_ CURVE TABLES. <br /> FIELDBOOK <br /> 471 -- Published by KEUFFEL & ESSER CO. _��� <br /> HOW TO USE CURVE TABLES. <br /> Table I. contains Tangents and Externals to a P curve. Tan.and <br /> Ext.to any other radius maybe found nearly enough,bydividing the Tan. <br /> or Ext.opposite the given Central Angle by the given degree of curve. <br /> To find Deg. of Curve, having the CentraF Angle and Tangent: <br /> Divide Tan.opposite the given Centralangle by the given Tangent. <br /> f/ rot•, To find Deg. of Curve, having.the Central Angle and External: <br /> Divide Ext. opposite the given Central Angle by the given External. <br /> 74 / 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 P curve Will <br /> be the Nat.Tan.or Nat,Ex.Sec. <br /> E%AMPLE. <br /> Wanted a Curve with an Ext.of about 12 ft. An L <br /> of Intersection or I. P.=23' 20' to the R. at Station <br /> 542+72. <br /> 01 Ext.in Tab. I opposite 23'20'=120.87 <br /> i 1 14120.87=12=10.07. Say a 10'Curve. 103 71 <br /> T Tan.in Tab. I opp.23'20'=1183.1 'r7,1 <br /> 1183.1=10=118.31. / -7.7 7— <br /> / <br /> 0,1 A. Correction for A.23'20'for a 10'Cur.=0.16 <br /> F —- 118.31- 0.16=118.47=corrected Tangent. <br /> (If corrected Ext.isuired find in same way) <br /> Ang.23'20'=23.33 =10=2.3333=L.C. <br /> NIS <br /> 0 <br /> r_ ,2 19} —def.for sta. 542 I. P.=sta. 542+72 <br /> I <br /> a a u <br /> \ <br /> 404911= -{-50 Tan.= 1 .18.47 <br /> Tai• J!( 9`J 70 1911= a a a 543 <br /> \ 90 49}'= a a a +50B.C.=sta. 541 { 53.53 <br /> 11'40'= a a a 543+ <br /> L.C.= 2 .33.33 <br /> 86.86 1 E.C.=Sta. 543- 86.86 <br /> — 100-53.53=46.47X3'(def.for 1 ft.of 10'Cur.)=139.41'= <br /> 2'19F=def.for sta.542. <br /> \� Def.for 50 ft.=2'30'for a 10'Curve. °' I <br /> \ Def.for 36.86 ft.=1'50j,'for a 10'Curve. <br /> p - .P.An9.E3•201 i <br /> V <br /> - 10•Curw <br /> 9,s3 1, o. // �syF,l. -- ,'"� ,"• u0g <br /> i <br /> w <br />