# Altitudes and orthocenter of a triangle

From Karnataka Open Educational Resources

An altitude of a triangle is a line segment that is drawn from the vertex to the opposite side and is perpendicular to the side. A triangle can have three altitudes. Point of intersection of these lines for different types of triangles is explored.

### Objectives

Introduce altitudes of a triangle and their point of concurrence.

### Estimated Time

30 minutes

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

Types of triangles and concept of altitudes should have been covered.

### Materials/ Resources needed

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

Geogebra resources: Concurrency of altitudes.ggb

Download this geogebra file from this link.

### Process (How to do the activity)

- Project the geogebra file and ask the following questions.

- Developmental Questions:

- Which type of triangle is this ?
- What is an altitude ?
- How do we construct an altitude ?
- What is the point of concurrence of 3 altitudes called ?
- Identify the position of point of concurrence in different triangles.

- Evaluation:

- What are the positions of orthocentre in different types of triangles.

- Question Corner:

- Find the applications of orthocentre.