# Perpendicular bisectors and circumcenter of a triangle

Circumcentre for different types of triangles is investigated with this activity and this further explores several geometric relationships related to the circumcentre and perpendicular bisectors.

### Objectives

Introduce perpendicular bisectors in a triangle and their point of concurrence.

30 minutes.

### Prerequisites/Instructions, prior preparations, if any

Ensure that circles, triangles, perpendicular bisectors and their constructions are covered

### Materials/ Resources needed

Digital resources: Laptop, geogebra file, projector and a pointer.

Geogebra files: Concurrency of perpendicular bisectors.ggb

### Process (How to do the activity)

1. Project the geogebra file and ask the following questions.
• Developmental Questions:
1. What is a perpendicular bisector ?
2. How do you construct it ?
3. Identify the point of intersection of perpendicular bisectors in different triangles.
4. What is circumcircle ?
• Evaluation:
1. How is circumradius determined ?
2. What parts of the circle is circumcircle touching ?
• Question Corner:
1. What are the practical applications of determining the circumcircle ?