| 180 | ( | a | − | 2 | ) | ÷ | 2 | × | ( | a | − | 1 | ) | + | 180 | = | 2400 |
| Left side of the equation = | 90 | ( | a | − | 2 | ) | ( | a | − | 1 | ) | + | 180 |
| 90 | ( | a | − | 2 | ) | ( | a | − | 1 | ) | + | 180 | = | 2400 |
| Left side of the equation = | 90 | a | ( | a | − | 1 | ) | − | 90 | × | 2 | ( | a | − | 1 | ) | + | 180 |
| = | 90 | a | ( | a | − | 1 | ) | − | 180 | ( | a | − | 1 | ) | + | 180 |
| = | 90 | a | a | − | 90 | a | × | 1 | − | 180 | ( | a | − | 1 | ) | + | 180 |
| = | 90 | a | a | − | 90 | a | − | 180 | ( | a | − | 1 | ) | + | 180 |
| = | 90 | a | a | − | 90 | a | − | 180 | a | + | 180 | × | 1 | + | 180 |
| = | 90 | a | a | − | 90 | a | − | 180 | a | + | 180 | + | 180 |
| = | 90 | a | a | − | 270 | a | + | 360 |
| 90 | a | a | − | 270 | a | + | 360 | = | 2400 |