# 3rd Grade - Isosceles, Equilateral And Right Triangles

 Grade Level: 3rd Skill: Shapes and Geometry Topic: Isosceles, Equilateral and Right Triangles Goal: Identify attributes of triangles (e.g., two equal sides for the isosceles triangle, three equal sides for the equilateral triangle, right angle for the right triangle). Skill Description: Measurement and Geometry: triangles, isosceles, equilateral, right angle The ability to classify different types of triangles and sort them based on defining characteristics.

### Sample Problems

 (1) What makes triangles different from each other? Triangles can be classified by their attributes, such as angles (right, acute, obtuse), sides (equilateral, isosceles, scalene), and size (similar and congruent). (2) Do the angles matter when sorting triangles? Angles: right triangles have one right (90 degree) angle. Acute triangles have all angles less than 90 degrees. Obtuse triangles have one angle more than 90 degrees. (3) What is the significance of the length of a triangle’s sides? Sides: Equilateral triangles have all three sides the same length. Isosceles triangles have two sides that are the same length. Scalene triangles have all three sides different lengths. (4) Can triangles be different sizes? Size: Similar triangles have the same shape, but they may be different sizes. Congruent triangles have the same size and shape. (5) Can triangle shapes be put together to make other things? Yes, triangles fit together to make all kinds of other shapes.

### Online Resources

 (1) (2) (3) (4) (5)