4. After 3 weeks, a plant is 8 centimeters tall. After 4 weeks, it has grown to 10 centimeters. If the plant grows following an arithmetic sequence, how tall will it be after 25 weeks?

Step 1 ：The plant's growth follows an arithmetic sequence. This means that the difference between the heights of the plant in consecutive weeks is constant.

Step 2 ：We can find this difference by subtracting the height of the plant in the third week from the height in the fourth week. \(10 - 8 = 2\)

Step 3 ：Once we have this difference, we can multiply it by the number of weeks minus 3 (since we already know the height at week 3) and add the result to the height at week 3 to find the height at week 25. \((25 - 3) * 2 + 8 = 52\)

Step 4 ：Final Answer: The plant will be \(\boxed{52}\) centimeters tall after 25 weeks.