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
Two Chords Crossing
1000
1
Altitude to the Hypotenuse of a Right Triangle
917
5
Cone Lateral Surface Area
917
4
Distance between Parallel Lines
917
2
Perpendicular Line Through a Point
917
2
Radius from a Circle Equation
917
2
Rectangle Diagonal Length
917
1
Right Triangle Altitude Problem
917
1
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