Final answer:
Each height level requires 5 more rods than the previous one. The pattern indicates that for a height of 4 scaffolding units, 21 rods are needed, and for a height of 5, 26 rods are needed.
Step-by-step explanation:
To determine how many metal rods are needed for scaffolding units of different heights, we need to identify the pattern in the sequence given. The pattern can be found by subtracting the number of rods needed for the previous height from the current height:
- Height 2 - Height 1 = 11 rods - 6 rods = 5 rods
- Height 3 - Height 2 = 16 rods - 11 rods = 5 rods
This shows that each additional height level requires 5 more rods than the previous one. Therefore, we can calculate the number of rods needed for heights 4 and 5 as follows:
- Height 4 = Height 3 + 5 rods = 16 rods + 5 rods = 21 rods
- Height 5 = Height 4 + 5 rods = 21 rods + 5 rods = 26 rods
Thus, the correct answer is:
A. Height 4 = 21 rods, Height 5 = 26 rods