{
 "source": "https://peabody.kids/flashcards/math-2d-shapes",
 "id": "math-2d-shapes",
 "title": "Flat Shapes and Polygons",
 "category": "math",
 "subject": "Math",
 "levels": [
  "k-2",
  "3-5",
  "6-8"
 ],
 "description": "Names and properties of 2D shapes, polygons by number of sides, and kinds of triangles and quadrilaterals.",
 "tags": [
  "shapes",
  "geometry",
  "polygons"
 ],
 "frontLabel": "Shape",
 "backLabel": "Facts",
 "cards": [
  [
   "Triangle",
   "3 sides, 3 angles"
  ],
  [
   "Quadrilateral",
   "4 sides, 4 angles"
  ],
  [
   "Pentagon",
   "5 sides"
  ],
  [
   "Hexagon",
   "6 sides"
  ],
  [
   "Heptagon",
   "7 sides",
   "Also called a septagon"
  ],
  [
   "Octagon",
   "8 sides",
   "A stop sign"
  ],
  [
   "Nonagon",
   "9 sides"
  ],
  [
   "Decagon",
   "10 sides"
  ],
  [
   "Hendecagon",
   "11 sides",
   "Also called an undecagon"
  ],
  [
   "Dodecagon",
   "12 sides"
  ],
  [
   "Circle",
   "All points the same distance from the center; no sides or corners"
  ],
  [
   "Oval (ellipse)",
   "A stretched circle"
  ],
  [
   "Square",
   "4 equal sides and 4 right angles"
  ],
  [
   "Rectangle",
   "4 right angles; opposite sides equal"
  ],
  [
   "Rhombus",
   "4 equal sides; opposite angles equal"
  ],
  [
   "Parallelogram",
   "Both pairs of opposite sides are parallel and equal"
  ],
  [
   "Trapezoid",
   "A quadrilateral with at least one pair of parallel sides"
  ],
  [
   "Kite",
   "A quadrilateral with two pairs of equal sides that meet side by side"
  ],
  [
   "Equilateral triangle",
   "All 3 sides equal; all angles 60 degrees"
  ],
  [
   "Isosceles triangle",
   "At least 2 equal sides and 2 equal angles"
  ],
  [
   "Scalene triangle",
   "No equal sides"
  ],
  [
   "Right triangle",
   "Has one 90-degree angle"
  ],
  [
   "Acute triangle",
   "All three angles are less than 90 degrees"
  ],
  [
   "Obtuse triangle",
   "Has one angle greater than 90 degrees"
  ],
  [
   "Regular polygon",
   "A polygon with all sides equal and all angles equal"
  ],
  [
   "Irregular polygon",
   "A polygon whose sides or angles are not all equal"
  ],
  [
   "Convex polygon",
   "A polygon with no angle pointing inward"
  ],
  [
   "Concave polygon",
   "A polygon with at least one angle pointing inward"
  ],
  [
   "Sum of angles in a triangle",
   "180 degrees"
  ],
  [
   "Sum of angles in a quadrilateral",
   "360 degrees"
  ],
  [
   "Sum of angles in a pentagon",
   "540 degrees"
  ],
  [
   "Sum of angles in a hexagon",
   "720 degrees"
  ],
  [
   "Sum of angles in an n-sided polygon",
   "(n − 2) × 180 degrees"
  ],
  [
   "Each angle of a regular hexagon",
   "120 degrees"
  ],
  [
   "Each angle of a regular pentagon",
   "108 degrees"
  ],
  [
   "Each angle of a regular octagon",
   "135 degrees"
  ],
  [
   "Number of diagonals of a quadrilateral",
   "2"
  ],
  [
   "Number of diagonals of a pentagon",
   "5"
  ],
  [
   "Number of diagonals of a hexagon",
   "9"
  ],
  [
   "Diagonal",
   "A segment joining two corners of a polygon that are not next to each other"
  ],
  [
   "Is a square a rectangle?",
   "Yes. A square is a rectangle with all sides equal."
  ],
  [
   "Is a square a rhombus?",
   "Yes. A square is a rhombus with right angles."
  ],
  [
   "Is a rectangle a parallelogram?",
   "Yes. Its opposite sides are parallel."
  ],
  [
   "Do the diagonals of a rectangle have equal lengths?",
   "Yes"
  ],
  [
   "Do the diagonals of a rhombus meet at right angles?",
   "Yes, and they bisect each other"
  ],
  [
   "Crescent",
   "A moon shape formed by two arcs"
  ],
  [
   "Semicircle",
   "Half of a circle"
  ],
  [
   "Quarter circle",
   "A quarter of a circle; a 90-degree sector"
  ],
  [
   "Star shape (pentagram)",
   "A five-pointed star drawn with five straight lines"
  ]
 ]
}