Category
Geometry
Circles, triangles, and the configurations that hide a right angle.
Geometry rewards seeing before calculating. A configuration that looks intractable usually has one hidden circle, one equal angle, or one similar triangle that collapses the whole problem at once.
These cover triangle centres, circles and cyclic quadrilaterals, areas and lengths, and the occasional coordinate bash when synthetic methods run out. Draw the figure accurately — an honest diagram is half the solution.
Latest problems
131 problems
Common External Tangent Length
1000
3
Cone Frustum Height Problem
1000
3
Median of a Triangle
1000
2
Point Inside a Rectangle
1000
2
Prism Vertices from Edge Count
1000
2
Right Triangle Incircle Radius
1000
2
Smallest Square Containing Two Points
1000
2
Triangle Base Length Sum
1000
2
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