Second only to the line, Triangle Geometry is the pure foundation of Geometry. Why? Take any polygon shape, and start joining the vertices with lines and you will create triangles. Triangles are the simplest of the polygon shapes, but dictate so much of geometry, both two and three dimensional!
Geometry is a huge amount of the elementary math curriculum and for this reason I have created a site devoted entirely to basic geometry. Be sure to check it out.
The formulas for calculating the area and perimeter of triangles must be learned and understood. A student must know what they are doing as well as how to do it. This will prove more and more important as their studies move into the realm of polygons and n-gons.
If your child has difficulty understanding the concept of the triangles area, consider cutting two copies of the same triangle from card. Place them together.
For a right angled triangle they will create a rectangle, for any other triangle, they will create a rhombus whose area is the same a rectangle! They used two triangles, so the area is half that of the rhombus.
Allow your child the time to fully explore triangles and their formula before progressing to polygons. The time spent here will be worth it!
Knowing how to identify triangles by lines and angles is a must for any K6 Student. Sometimes questions in the Triangle Geometry are as basic as identifying what type of triangle a shape is. Knowing the vocabulary is a must.
There are three types of triangles, and two methods of identifying each of them. These methods can also be combined. For example a triangle can be a right Isosceles.
Equilateral, Isosceles, Scalene
Right, Obtuse, Acute
To learn everything about triangles and their associations with different shapes is a huge amount of information - too big for this site. That is why I have created www.K6-Geometric-Shapes - a site devoted entirely to elementary geometry.
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