Classifying Polygons Lesson 9-3
Classifying Triangles Triangles have 3 sides and can be classified or named based on 2 things—their angles and their sides.
Triangles By angles: Acute—all three angles are acute. Less than 90 degrees Right—has one right or 90 angle. Obtuse—has one obtuse angle. Greater than 90 degrees
Triangles By sides: Equilateral—all three sides are equal. Isosceles—two sides are equal. Scalene—all three sides are different.
Try This Give two names for the following:
Try This Give two names for the following: Scalene, right
Try This Give two names for the following:
Try This Give two names for the following: Equilateral, acute
Try This Give two names for the following:
Try This Give two names for the following: Isosceles, acute
Try This Give two names for the following:
Try This Give two names for the following: Scalene, obtuse
Quadrilaterals Quadrilaterals have FOUR sides. These are examples of quadrilaterals:
Classifying Quadrilateral All four sided figures are quadrilaterals. They may or may not be symmetrical.
Quadrilaterals Parallelograms have 2 sets of parallel lines.
Quadrilaterals Parallelograms have 2 sets of parallel lines. Rectangles have parallel lines and 90 angles.
Quadrilaterals Parallelograms have 2 sets of parallel lines. Rectangles have parallel lines and 90 angles. Rhombus has four equal sides.
Quadrilaterals Squares have four equal sides and four 90 angles.
Quadrilaterals Squares have four equal sides and four 90 angles. Trapezoids have exactly one pair of parallel lines.
Try This Name all the names that apply for this shape:
Try This Name all the names that apply for this shape: Quadrilateral, parallelogram, rectangle
Try This List all the names for this shape:
Try This List all the names for this shape: Quadrilateral, parallelogram, rhombus
Try This List all the names for this shape:
Try This List all the names for this shape: Quadrilateral, trapezoid
Bonus question Are all squares also rectangles?
Bonus question Are all squares also rectangles? Yes
Bonus question Are all squares also rectangles? Yes Are all rectangles also squares?
Bonus question Are all squares also rectangles? Yes Are all rectangles also squares? No