Maths Challenge
Maths challenge.net: Maximum Square
A challenging proof like geometry of finding the square inscribed in a triangle.
Maths Challenge
Maths challenge.net: Sloping Square
A geometry problem of finding the area of a sloped square within a square.
Maths Challenge
Maths challenge.net: Triangle in a Square
A "three star" geometry problem requiring some prior knowledge in math and proofs to maximize the area of an inscribed triangle in terms of the hypotenuse.
National Council of Teachers of Mathematics
Nctm: Illuminations: Proof Without Words: Completing the Square
Use this interactive geometric proof to complete the square using geometry.
Maths Challenge
Maths challenge.net: Shaded Square
A problem of finding the fraction of a square that is shaded given criterion. Students will have to use their mathematical reasoning and triangle solving skills to solve this area problem.
Other
Antonio Gutierrez: Geometry From the Land of the Incas
Discovering the properties of constructions, seeing proofs in action, and viewing problems come to life here with this wonderful use of technology in the classroom. Single steps are explained and illustrated one at a time so that the...
Alabama Learning Exchange
Alex: Geometrica Fights Back!
This activity is designed to give learners practice with the properties of special quadrilaterals (parallelograms, rectangles, rhombuses, squares, trapezoids, and kites). The students are provided with a "murder mystery" sheet with...