Ohio Resource Center
Content Supports - Activities and rich problems
Identify the Shape
Discipline
Mathematics
9, 10, 11, 12
Professional Commentary

Given several pieces of information, identify a shape in a diagram and prove your answer is correct. This problem is one of Stella's Stunners, a collection of challenging and entertaining mathematical problems to intrigue students in grades 6 - 12. The Stella problems are ideal for promoting inquiry, problem solving, and classroom discussion of key mathematical ideas. Sample solutions are provided for each problem, but students may find other solutions and may even compete with their classmates to find the most creative solution path. Stella problems can be printed out individually or in sets designed for Pre-Algebra, Algebra I, Geometry, Algebra II/Trigonometry, or Pre-Calculus. Problems can be printed with or without solutions and can be added to ORC Collections. The Stella website includes a wealth of teaching resource materials, including an essay on the value of problem solving, a list of 25 useful problem-solving heuristics, a biography of Stella, several tips for using Stella problems in the classroom, and listings of the Stella library by course, by title, and by Stella number. ORC hopes you enjoy the Stella problems, and we invite you to share with Stella's author any experiences you have using Stella problems with your students. (Stella number 3510.11)(author/sw)

Common Core State Standards for Mathematics
Standards for Mathematical Practice
CCSS.Math.Practice.MP1
Make sense of problems and persevere in solving them.
CCSS.Math.Practice.MP3
Construct viable arguments and critique the reasoning of others.
High School - Geometry
Congruence
Prove geometric theorems
Similarity, Right Triangles, and Trigonometry
Prove theorems involving similarity
Circles
Understand and apply theorems about circles