Geometry-Equality of triangles
Area
Math
Duration
2 sessions
Dimension of the advised group of students
15 - 20 students, divided in 5 groups
Specific objectives
The teaching of Euclidean geometry is important for students. Children have difficulties and therefore the lesson should be taught in a way that makes them understand that geometry is a game that will help them open their minds, which will facilitate them in all areas of their lives. The initial approach should be intuitive and exploratory and then the immersion should be in strict mathematical terms.
As in all the teaching units, the threefold approach is followed:
Observe, Formulate, Demonstrate.
Needed Materials
Computer or laptop, internet, pen, paper, geometric instruments
Software
The activities shall be carried out on site.
Description
'Equal triangles' is a basic teaching unit in geometry at all levels. The definition of equality of two triangles requires the equality of 6 elements. Learning the equality criteria enables students to construct 2 triangles with only 3 elements. If given 2 pairs of triangles, students can experiment to understand that with appropriate displacements the triangles are equal. The use of new technologies enables students to significantly reduce the difficulties encountered at the observation stage. Students are given worksheets ,which in combination with programs (Geogebra) can be used to observe and then formulate the question. Obviously all this with the help and guidance of the teacher.
Procedure on how to put in practice
Students have pairs of equal triangles on their worksheets that are not placed symmetrically. With the help of transparent paper, they are asked to place the triangles on top of each other so that their elements are identical. They understand when the triangles are equal.
Then using the platform (Geogebra), they are asked to construct 2 pairs of equal line segments that intersect each other to form equal angles. Then they are asked to form the triangles in the figure and observe that given these data the triangles are equal. Thus at the end the students themselves draw the conclusion and formulate the First Equality Criterion. Exercises are given so that the students can apply the theorem that they themselves formulated. A general proof is not necessary for this age group.
