Formation of a triangle
Jump to navigation
Jump to search
The printable version is no longer supported and may have rendering errors. Please update your browser bookmarks and please use the default browser print function instead.
Introducing formation of a shape with least number of lines and the space enclosed by these lines form a geometric shape.The key geometric concepts that are related with this are explained.
Objectives
- Understand formation of triangles
- Recognize elements of triangle
- Introduce concepts of exterior angle.
Estimated Time
30 minutes
Prerequisites/Instructions, prior preparations, if any
Prior knowledge of point, lines, angles, parallel lines
Materials/ Resources needed
- Digital : Computer, geogebra application, projector.
- Non digital : Worksheet and pencil
- Geogebra files : “Introduction to a triangle.ggb”
Download this geogebra file from this link.
Process (How to do the activity)
- Use the geogebra file to illustrate. The questions below will are used to interact with the geogebra sketch.
- How many lines are there? Are the lines meeting?
- Are the two lines parallel? How can you say they are parallel or not?
- How many angles are formed at the point of intersection?
- What is the measure of the total angle at the point of intersection of two lines?
- Of the four angles formed which of the angles are equal? What are they called?
- Do the three intersecting lines enclose a space? How does it look? It is called a triangle.
- What are the points of intersection of these three lines called?
- The line segments forming the triangle are called sides.
- How many angles are formed when three lines intersect with each other?
- How many angles are enclosed by the triangle?
Evaluation at the end of the activity
- Can there be a closed figure with less than three sides?
- Can the vertices of the triangle be anywhere on a plane?
- What will happen if the three vertices are collinear?