A triangle is a two-dimensional, closed shape with exactly three straight sides, three vertices, and three angles. The defining attributes remain unchanged when a triangle is rotated, reflected, resized, or drawn with unequal sides, so appearance and orientation do not determine whether a shape is a triangle; formal angle measurement and more advanced classification are not included here.
A triangle is a closed, flat shape with:
The shape can be turned, flipped, made bigger or smaller, or have sides of different lengths. It is still a triangle if it has these three features.
Example:
Look at a shape that is tilted to one side. It has three straight sides, three corners, and three angles. Its sides are not all the same length.
Check it step by step:
Because all the checks are true, the shape is a triangle.
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