Answer:
It seems there is a typo in your question regarding the length of the shadow. It should be 30m instead of 3om. Assuming you meant that, you can solve this problem using similar triangles. Here’s how:
Given:
- Height of the flag mast: 5 meters
- Length of the flag mast's shadow: 30 meters
Let’s assume the height of the building is \( h \) meters, and the length of the building's shadow is also 30 meters (since it's not mentioned otherwise).
Using the property of similar triangles:
\[
\frac{\text{Height of flag mast}}{\text{Length of flag mast's shadow}} = \frac{\text{Height of building}}{\text{Length of building's shadow}}
\]
\[
\frac{5}{30} = \frac{h}{30}
\]
Since the shadows are equal, we have:
\[
5 = h
\]
Therefore, the height of the building is also 5 meters.