Rules Relating to Circles and Ovals

 

·               The circumference of a circle is the diameter x 3.1416.

·               The diameter of a circle is the circumference multiplied by .31831.

·               The area of a circle is the diameter x itself x .7854.

·               The area of an oval is the longest diameter x the shortest x .7854.

·               A circle is .7854 times as heavy as a square of the same size, i.e., the loss in cutting a circle from a square is .2146 of the weight of the square.

 

TABLE

 

Circles and Squares

(Circumferences and Areas)

 

 

Circum-

Area in

Area in

 

 

Circum-

Area in

Area in

Size in

ference

Square

Square

 

Size in

ference

Square

Square

inches

in Inches

inches

Inches

 

inches

in Inches

inches

inches

1/4

.7854

.0491

.0625

 

10 1/4

32.20

82.52

105.06

1/2

1.571

.1964

.2500

 

10 1/2

32.99

86.59

110.25

3/4

2.356

.4418

.5625

 

10 3/4

33.77

90.76

115.56

1

3.142

.7854

1.000

 

11

34.56

95.03

121.00

1 1/4

3.927

1.227

1.563

 

11 1/4

35.34

99.40

126.56

1 1/2

4.712

1.767

2.250

 

11 1/2

36.13

103.87

132.25

1 3/4

5.498

2.405

3.063

 

11 3/4

36.91

108.43

138.06

2

6.283

3.142

4.000

 

12

37.70

113.10

144.00

2 1/4

7.069

3.976

5.063

 

12 1/4

38.48

117.86

150.06

2 1/2

7.854

4.909

6.250

 

12 1/2

39.27

122.72

156.25

2 3/4

8.639

5.940

7.563

 

12 3/4

40.06

127.68

162.56

3

9.425

7.069

9.000

 

13

40.84

132.73

169.00

3 1/4

10.21

8.296

10.56

 

13 1/4

41.63

137.89

175.56

3 1/2

11.00

9.621

12.25

 

13 1/2

42.41

143.14

182.25

3 3/4

11.78

11.04

14.06

 

13 3/4

43.20

148.49

189.06

4

12.57

12.57

16.00

 

14

43.98

153.94

196.00

4 1/4

13.35

14.19

18.06

 

141/4

44.77

159.49

203.06

4 1/2

14.14

15.90

20.25

 

14 1/2

45.55

165.13

210.25

4 3/4

14.92

17.72

22.56

 

14 3/4

46.34

170.87

217.56

5

15.71

19.64

25.00

 

15

47.12

176.72

225.00

5 1/4

16.49

21.65

27.56

 

15 1/4

47.91

182.65

232.56

5 1/2

17.28

23.76

30.25

 

15 1/2

48.69

188.69

240.25

5 3/4

18.06

25.97

33.06

 

15 3/4

49.48

194.83

248.06

6

18.85

28.27

36.00

 

16

50.27

201.06

256.00

6 1/4

19.64

30.68

39.06

 

16 1/4

51.05

207.39

264.06

6 1/2

20.42

33.18

42.25

 

16 1/2

51.84

213.83

272.25

6 3/4

21.21

35.78

45.56

 

16 1/4

52.62

220.35

280.56

7

21.99

38.48

49.00

 

17

53.41

226.98

289.00

7 1/4

22.78

41.28

52.56

 

17 1/4

54.19

233.71

297.56

7 1/2

23.56

44.18

56.25

 

17 1/2

54.98

240.53

306.25

7 3/4

24.35

47.17

60.06

 

17 3/4

55.76

247.45

315.06

8

25.13

50.27

64.00

 

18

56.55

254.47

324.00

8 1/4

25.92

53.46

68.06

 

18 1/4

57.33

261.59

333.06

8 1/2

26.70

56.75

72.25

 

18 1/2

58.12

268.80

342.25

8 1/4

27.49

60.13

76.56

 

18 3/4

58.91

276.12

351.56

9

28.28

63.62

81.00

 

19

59.69

283.53

361.00

9 1/4

29.06

67.20

85.56

 

19 1/4

60.48

291.04

370.56

9 1/2

29.85

70.88

90.25

 

19 1/2

61.26

298.65

380.25

9 3/4

30.63

74.66

95.06

 

19 3/4

62.05

306.36

390.06

10

31.42

78.54

100.00

 

20

62.83

314.16

400.00