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j ►�, �� CURVE TABLES. _ ---_ - C�'Tkm- 3 J" Published by KEUFFEL & ESSERCO. � . HOW TO USS CURVE TABLES:�''`�-- Table I. contains Tangents and Externals to a 1°curve. Tan.and _ _ :xt.toanyotherradiusmaybefoundnearlyenough,bydividingtheTan. 0 or Ext.opposite the given Central Angle by the given degree of curve. To find Deg. of Curve, having the Central Angle and Tangent: Divide Tan. opposite the given Central Angle by the given Tangent. 1 3 SSV Z $ To find Deg. of Curve, having the Central Angle and External: _'7, Divide Ext.opposite the given Central Angle by the given External. rf, 'f }o ,oTo find Nat.Tap.and Nat.Ex.Sec.for any angle by Table I.:Tan. 3 ` 13- -- f Qr Ext.of twice the given angle divided by the radius of a 1°curve will I� �g 4.7 J- 3 1 7 L De the Nat.Tan.or Nat.Ex,Sec. EXAMPLE. g t�. � o 3,zz �b X1 .3 7 k4- _ _ - Wantd a Curve with an Ext, of about 12 ft. Angle -SL 6 j 1 Y, r / .L / -`1 L�' of Intersection or 1, P.=230 20' to the R. at Station- -7 . "�f -d- a a} _ I�,7 -J I L.7-- 542+72. y o 4 8 3-1 o Ext.in Tab. I opposite 230 20'=120.87 F�' 3 ' .� G {�}'-�-- - - G ! 120.87=12=10.07. Say a 10°Curve. 1-� l 3�_ Tan.in Tab. I opp.23°20'=1183.1 1183.1=10=118.31. 7 � a79 o 3 � 1�i•7 c Correction for A.23°20'for a 10°Cur.=0.16 =corrected • - ._� _ ' 1. 3_ - (If corrected Ext i8 d required finn same way) /7,7 3 . r �� ° Ang.23 20'=23.33'-- 10 2.3333 L.C. y,1 3 4 49"=def.for sta. 542 L P.=sta. 542+72 10 y y o it cc a 1 .18.47 ..f",t" y 1 '� I `} -� 70 191,'- -�a �a a 543+50 Tan._ _'�-...` 3 1 t._.!- /9.�� 9°49a'= a u a +50 B. C. sta. 541 {53.531 ,f 3 G 11A 40'= a a a 8 543+ L. C.= 2. .33.33 s^ 3 4 13 , 86.86 E.C.=Sta. 543+86.86 14,--- `j _s 100-53.53=46.47 X3'(def,for 1 ft.of 10°Cur.)=139.41' � , 3 7 -0 r v- ,r2°19;'=def.for sta.542. y 3 N 3 g I Br'r Def.for 50 ft.=2°30'fora 10°Curve. J _,_.� -----._ _ __.___._ Def.for 36.86 ft. 1*50j'for a 10°Curve. Z G l�• 1 - d fu _ - -'* 3.31 I .•( 3 �* lo-curve �o o y %411 Q/ � J i J •