Final answer:
To find the first term of the sequence where 45 is the third term, divide 45 by 3 twice. After dividing twice, we find out that the first term is 5.
Step-by-step explanation:
To determine the first term of the sequence where 45 is the third term, we should identify the pattern or rule governing the sequence. The given sequence is 45, 135, 405, 1215. By observation, each term is multiplied by 3 to get the next term (45 × 3 = 135, 135 × 3 = 405, and 405 × 3 = 1215). Since 45 is stated to be the third term, to find the first term, we need to divide 45 by 3 twice. In step-by-step fashion:
- Divide 45 by 3 to find the second term: 45 / 3 = 15.
- Divide 15 by 3 to find the first term: 15 / 3 = 5.
Therefore, the first term of the sequence is 5.