| ( | V | × | 1 | + | V | × | 2 | ) | × | 180 | = | 900 |
| 方程左边 = | V | × | 1 | × | 180 | + | V | × | 2 | × | 180 |
| = | V | × | 180 | + | V | × | 360 |
| = | 540 | V |
| 540 | V | = | 900 |
| V | = | 900 | ÷ | 540 |
| = | 900 | × | 1 540 |
| = | 5 | × | 1 3 |
| V | = | 5 3 |
| V | = | 1.666667 |
| ( | V | × | 1 | − | V | × | 2 | ) | × | 270 | = | 900 |
| 方程左边 = | V | × | 1 | × | 270 | − | V | × | 2 | × | 270 |
| = | V | × | 270 | − | V | × | 540 |
| = | - | 270 | V |
| - | 270 | V | = | 900 |
| - | 900 | = | 270 | V |
| 270 | V | = | - | 900 |
| V | = | - | 900 | ÷ | 270 |
| = | - | 900 | × | 1 270 |
| = | - | 10 | × | 1 3 |
| V | = | - | 10 3 |
| V | = | - 3.333333 |