Education Technology

# Activities

Middle

50 Minutes

• ##### Device
• TI-Nspire™ CX
• TI-Nspire™ CX CAS
• ##### Software

TI-Nspire™
TI-Nspire™ CAS

4.5

## Inside Out

#### Activity Overview

Students explore the concept of 'centre' using a range of familiar shapes. The dynamic geometry environment on TI-Nspire is then used to construct a triangle. Using the perpendicular bisector tool students locate the circumcentre of the triangle then use congruent triangles to establish a proof.

#### Objectives

• ACMMG243– Formulate proofs involving congruent triangles and angle properties
• ACMMG201– Develop the conditions for congruence of triangles

#### Vocabulary

• Perpendicular
• Bisector
• Vertex
• Congruent
• S.A.S - Congruency Condition
• Reflection
• Transformation

#### About the Lesson

Students explore the concept of centre through a variety of shapes visually, dynamically and through paper folding. Students then use the TI-Nspire Geometry Application to construct a dynamic representation of the circumcentre of a triangle followed by a proof.