According to the condition of the problem, the period of revolution of the planet around the Sun is 4.5 years, therefore, this is the outer planet. Therefore, to calculate the synodic period, we will use the formula 1 / S = 1 / P-1 / T -, where P = 1 year is the period of the Earth’s revolution around the Sun, T is the period of the planet’s revolution around the Sun. 1 / S = 1 – 1 / 4.5 = 0.88888; S = 1.125 (years).
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.