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Problems
Contests
National and Regional Contests
Iran Contests
Iran MO (1st Round)
2018 Iran MO (1st Round)
9
9
Part of
2018 Iran MO (1st Round)
Problems
(1)
Area of wildfire in the forest park - Iran First Round 2018, P9
Source:
3/7/2021
A part of a forest park which is located between two roads has caught fire. The fire is spreading at a speed of
10
10
10
kilometers per hour. If the distance between the starting point of the fire and both roads is
10
10
10
kilometers, what is the area of the burned region after two hours in kilometers squared? (Assume that the roads are long, straight parallel lines and the fire does not enter the roads)
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<span class='latex-bold'>(A)</span>\ 200\sqrt 3\qquad<span class='latex-bold'>(B)</span>\ 100 \sqrt 3\qquad<span class='latex-bold'>(C)</span>\ 400\sqrt 3 + 400 \frac{\pi}{3} \qquad<span class='latex-bold'>(D)</span>\ 200\sqrt 3 + 400 \frac{\pi}{3} \qquad<span class='latex-bold'>(E)</span>\ 400\sqrt 3
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area