Building 67654
The 15 m high building is 30 m away from the river bank. The river's width can be seen from the roof of this building at an angle of 15 °. How wide is the river?
Correct answer:

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You need to know the following knowledge to solve this word math problem:
- algebra
- expression of a variable from the formula
- planimetrics
- right triangle
- triangle
- goniometry and trigonometry
- sine
- cosine
- tangent
- arctangent
Units of physical quantities:
Grade of the word problem:
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