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This problem will need solving in stages by most students.
Perhaps beginning by establishing the required line ratio.
Then by remembering a familiar figure where that particular ratio can be found.
Deciding how that figure can be constructed on the given triangle to locate a useful point.
Finally creating the required line, parallel to the base, across the triangle.
Half a Triangle
Age 14 to 16
Challenge Level 
This problem will need solving in stages by most students.
Perhaps beginning by establishing the required line ratio.
Then by remembering a familiar figure where that particular ratio can be found.
Deciding how that figure can be constructed on the given triangle to locate a useful point.
Finally creating the required line, parallel to the base, across the triangle.
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