Answer:
448
Explanation:
This is a proportion question. Keep the heights on one side of the proportion and the shadow length on the other.
height ratio shadow ratio
40 cm / x = 25 / 280 Cross multiply
25x = 40 * 280 Combine
25x = 11200 Divide by 25
x = 11200/25
x = 448 cm
The height of the corn plant is 448 cm