Final answer:
The willow's height is 3/8 of the poplar's height when the ratio of the heights of a willow to a poplar is given as 3:5. This fraction is obtained by dividing the first number in the ratio by the sum of both numbers in the ratio.
Step-by-step explanation:
The question is asking to find what fraction of the poplar's height is the height of the willow if the ratio given is 3:5. This can be interpreted as for every 3 units of height the willow has, a poplar has 5 units.
Hence, to find the fraction of the poplar's height that corresponds to the willow's height, you can express the willow's height as a fraction of the poplar's height by dividing the willow's height by the total height.
Let's set up the proportion by using the ratio 3:5. Since these two numbers represent parts of a whole, we can consider the whole as 3 + 5 = 8.
Therefore, the willow's height is 3/8 of the poplar's height. This is because a ratio of 3:5 can be directly converted into the fraction 3/(3+5), which simplifies to 3/8.