| helf circle | 1 1/2 circle | 2 1/2 circle | 3 1/2 circle | 4 1/2 circle | 5 1/2 circle | 6 1/2 circle | 7 1/2 circle | 8 1/2 circle | 9 1/2 circle | 10 1/2 circle | 11 1/2 circle | 12 1/2 circle | 13 1/2 circle | 14 1/2 circle | 15 1/2 circle | 16 1/2 circle | 17 1/2 circle | 18 1/2 circle | 19 1/2 circle | 20 1/2 circle | 21 1/2 circle | 22 1/2 circle | 23 1/2 circle | 24 1/2 circle | 25 1/2 circle | 26 1/2 circle | 27 1/2 circle | 28 1/2 circle | 29 1/2 circle | 30 1/2 circle | 31 1/2 circle | 32 1/2 circle | 33 1/2 circle | 34 1/2 circle | 35 1/2 circle | 36 1/2 circle | 37 1/2 circle | 38 1/2 circle | 39 1/2 circle | 40 1/2 circle | 41 1/2 circle | 42 1/2 circle | 43 1/2 circle | 44 1/2 circle | 45 1/2 circle | 46 1/2 circle | 47 1/2 circle | 48 1/2 circle | 49 1/2 circle | 50 1/2 circle | 51 1/2 circle | 52 1/2 circle | 53 1/2 circle | 54 1/2 circle | 55 1/2 circle | 56 1/2 circle | 57 1/2 circle | 58 1/2 circle | 59 1/2 circle | 60 1/2 circle | 61 1/2 circle | 62 1/2 circle | 63 1/2 circle | 64 1/2 circle | 65 1/2 circle | 66 1/2 circle | 67 1/2 circle | 68 1/2 circle | 69 1/2 circle | 70 1/2 circle | 71 1/2 circle | 72 1/2 circle | 73 1/2 circle | 74 1/2 circle | 75 1/2 circle | 76 1/2 circle | 77 1/2 circle | 78 1/2 circle | 79 1/2 circle | 80 1/2 circle | 81 1/2 circle | 82 1/2 circle | 83 1/2 circle | 84 1/2 circle | 85 1/2 circle | 86 1/2 circle | 87 1/2 circle | 88 1/2 circle | 89 1/2 circle | 90 1/2 circle | 91 1/2 circle | 92 1/2 circle | 93 1/2 circle | 94 1/2 circle | 95 1/2 circle | 96 1/2 circle | 97 1/2 circle | 98 1/2 circle | 99 1/2 circle | 100 1/2 circle |
| sextant | 3 " | 6 " | 9 " | 12 " | 15 " | 18 " | 21 " | 24 " | 27 " | 30 " | 33 " | 36 " | 39 " | 42 " | 45 " | 48 " | 51 " | 54 " | 57 " | 60 " | 63 " | 66 " | 69 " | 72 " | 75 " | 78 " | 81 " | 84 " | 87 " | 90 " | 93 " | 96 " | 99 " | 102 " | 105 " | 108 " | 111 " | 114 " | 117 " | 120 " | 123 " | 126 " | 129 " | 132 " | 135 " | 138 " | 141 " | 144 " | 147 " | 150 " | 153 " | 156 " | 159 " | 162 " | 165 " | 168 " | 171 " | 174 " | 177 " | 180 " | 183 " | 186 " | 189 " | 192 " | 195 " | 198 " | 201 " | 204 " | 207 " | 210 " | 213 " | 216 " | 219 " | 222 " | 225 " | 228 " | 231 " | 234 " | 237 " | 240 " | 243 " | 246 " | 249 " | 252 " | 255 " | 258 " | 261 " | 264 " | 267 " | 270 " | 273 " | 276 " | 279 " | 282 " | 285 " | 288 " | 291 " | 294 " | 297 " | 300 " |
1/2 circle or half circle is equal to 360°/2 = 180°. Plural name is helf circles.
| Name of unit | Symbol | Definition | Relation to SI units | Unit System |
|---|---|---|---|---|
| helf circle | 1/2 circle | ≡ 180 ° | = 3.1415926 rad | Metric system SI |
| helf circles | sextants | helf circles | sextants |
|---|---|---|---|
| 1 | ≈ 3 | 6 | ≈ 18 |
| 2 | ≈ 6 | 7 | ≈ 21 |
| 3 | ≈ 9 | 8 | ≈ 24 |
| 4 | ≈ 12 | 9 | ≈ 27 |
| 5 | ≈ 15 | 10 | ≈ 30 |
sextant is the unit of plane angle, equals to 60°.
| Name of unit | Symbol | Definition | Relation to SI units | Unit System |
|---|---|---|---|---|
| sextant | " | ≡ 60° | ≈ 1.047198 rad | Metric system SI |
| sextants | helf circles | sextants | helf circles |
|---|---|---|---|
| 1 | ≈ 0.33333333333333 | 6 | ≈ 2 |
| 2 | ≈ 0.66666666666667 | 7 | ≈ 2.3333333333333 |
| 3 | ≈ 1 | 8 | ≈ 2.6666666666667 |
| 4 | ≈ 1.3333333333333 | 9 | ≈ 3 |
| 5 | ≈ 1.6666666666667 | 10 | ≈ 3.3333333333333 |
| helf circles | sextants |
|---|---|
| 1 | ≈ 3 |
| 0.3333333 | ≈ 1 |
| Symbol | Definition |
|---|---|
| ≡ | exactly equal |
| ≈ | approximately equal to |
| = | equal to |
| digits | indicates that digits repeat infinitely (e.g. 8.294 369 corresponds to 8.294 369 369 369 369 …) |