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geometry of 2D
Geometry of 2D shapes
| Term | Definition |
|---|---|
| Area | The number of square units needed to cover a given surface |
| Trapezoid | A quadrilateral with exactly one pair of parallel sides |
| Perimeter | The distance around a polygon |
| Circumference | The distance around a circle |
| Surface Area | The sum of the areas of the faces or surfaces of a three-dimensional figure |
| Prism | A polyhedron that has two congruent polygon shaped bases and other faces that are parallelograms |
| Volume | The number of cubic units needed to fill a given space |
| Parallelogram | A quadrilateral with two pairs of parallel sides |
| Diameter | A line segment that passes through the center of a circle and has end-points on the circle or the length of that segment |
| Radius | A line segment with one end-point at the center of a circle and the other end-point on the circle or that length of the segment |
| area of a rectangle | length x width |
| area of a parallelogram | base x height |
| area of a trapezium | ((a +b) x h)/2 |
| area of a circle | 3.142 x radius x radius |
| Area of a triangle | A = (b x h) divided by 2 |
| Circumference of circle | Pi x d |
| Perimeter of a rectangle (and parallelograms) | A = 2(L x W) |
| Triangle Area = | 1/2 x base x perpendicular height |
| Square Area = | base x base |
| Rectangle Area = | base x height |
| Parallelogram Area = | base x perpendicular height |
| Trapezium Area = | 1/2 x height x (top + bottom) |
| Circle Area = | π x r squared |
| Area (rhombus) | bxh |
| Acute Triangle | A triangle with 3 acute angles |
| Right Triangle | A triangle that has a 90 degree angle (right angle) |
| Obtuse Triangle | A triangle with one angle that is greater than 90 degrees. |
| Square | Four equal sides and four right angles |
| Rhombus | A parallelogram with four equal sides |
| Trapezoid(US)/Trapezium(UK) | A quadrilateral with exactly one pair of parallel sides |
| Pentagon | 5 sided polygon |
| Octagon | 8-sided polygon |
| Nonagon | 9 sided polygon |
| Decagon | 10 sided polygon |
| Heptagon | 7 sided polygon |
| Hexagon | 6 sided polygon |