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f <br /> so 00 <br /> CURVE TABLES. r <br /> Publishad.by KEUFFEL & ESSER CO. <br /> HOW TO USE CURVE TABLES. <br /> -0 6 Table I. contains Tangents and Externals to-a V durve. Tan.and <br /> 7 6 Ext.to any other radius may be found nearly enough,by dividing the Tan. <br /> ¢ - or Ext.opposite the given Central An by the 'ven degree of curve. <br /> To find Deg, of Curve,having the Cen ' Angle and Tangent: <br /> Dividefind.opposite <br /> posite the given Central An�le by the given Tangent. <br /> a! Deg. of Curve, having the Central Angle and External: <br /> `f• 'L'S 7 7�' ` Divide Ext.opposite the given Central Angle by the given External. ! <br /> d To find Nat.Tata.and Nat..Ex.See.for an angle by Table I.:Tan. <br /> S D o �' / or Ext.of twice the riven angle divided by the radius of a P curve will <br /> be the Nat.Tan.or Nat.Ex.Sec. <br /> — o p <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 /> / �, O6 Ext.in Tab.I op�ppoo�s�'te23°.20'=1W.87 <br /> �y ', y (� 77' I20.87�F 12 10A7.; Say a 10•:Curve, <br /> �) d J !� Tan.in Tab.I opp.23°20'—1183.1 <br /> 6 _- 1183.1+10=118.31. <br /> Correction for A.23°20'for a 10°Cur.—0.16 <br /> { R <br /> 118.31+0.16—118.47—corrected Tangent.. <br /> O 4- j S3 F (If corrected-Ext.isuired find in same way) <br /> „{�✓.r <br /> Ang.23°20'.=23.�+10=2.3333—L.C. <br /> ►`�'.'' +^ �1 2°19F—def.for sta. 542 L P. sta. 542+72 <br /> 4°4911= a a a x-50 Tan.— 1 .18.47 <br /> 7°19i'— a a a 543 <br /> 9°49j'- a a a +W B.C.=sta. 541 {-53.53 <br /> T <br /> 11°401— a a s 543 {- L.C.— 2 .33.33 <br /> 86.86 E.C.—Sta, 543-}88.86 <br /> 100-53.53-46.47X3'(def.for 1 ft.of 10°Cur.)-139.411= <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 50+}'for a 10°Curve. <br /> e <br /> f x _ <br /> � .rr"y.sa•sv <br /> 101cur" ` <br /> q <br /> A <br />