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Daniel GeometryTerms
Question | Answer |
---|---|
acute triangle | A triangle in which all three angles are acute |
angle | A figure formed by two rays that have a common endpoint |
chord | A line segment with its endpoints on a circle |
circle | A closed plane figure with all points on the figure the same distance from the center |
circumference | The distance around a circle |
closed figure | A figure that begins and ends at the same point |
cone | A solid figure that has a circular base and one vertex |
congruent | Having the same size and shape |
congruent figures | Figures that have the same size and shape |
coordinate plane | A plane formed by two intersecting and perpendicular number lines called axes |
coordinates | The numbers in an ordered pair |
cube | A solid figure with six congruent square faces |
cylinder | A solid figure that has two parallel bases that are congruent circles |
degree (°) | A unit for measuring angles and temperature |
diameter | A line segment that passes through the center of a circle and has its endpoints on the circle |
dimension | A measure in one direction; the length, width, or height of a figure |
edge | The line segment where two faces of a solid figure meet |
equilateral triangle | A triangle with three congruent sides |
face | A polygon that is a flat surface of a solid figure |
figurate numbers | Numbers that can be represented by geometric figures |
hexagon | A polygon with six sides and six angles |
hypotenuse | In a right triangle, the side opposite the right angle; the longest side in a right triangle |
intersecting lines | Lines that cross at exactly one point |
isosceles triangle | A triangle with two congruent sides |
line | A straight path in a plane that goes on forever in opposite directions |
line segment | A part of a line that includes two points, called endpoints, and all of the points between them |
line symmetry | A figure has line symmetry if a line can separate the figure into two congruent parts |
obtuse angle | An angle whose measure is greater than 90° and less than 180° |
obtuse triangle | A triangle that has one obtuse angle |
octagon | A polygon with eight sides |
ordered pair | A pair of numbers used to locate a point on a coordinate plane; the first number tells how far to move horizontally and the second number tells how far to move vertically |
parallel lines | Lines in a plane that never intersect |
parallelogram | A quadrilateral whose opposite sides are parallel and congruent |
pentagon | A polygon with five sides |
perpendicular lines | Two lines that intersect to form four right angles |
plane | A flat surface that extends without end in all directions |
plane figure | A figure which lies in a plane |
point | An exact location in space, usually represented by a dot |
point symmetry | When a figure can be turned half way about a central point and still look the same |
polygon | A closed plane figure formed by three or more line segments |
polyhedron | A solid figure with flat faces that are polygons |
prism | A solid figure that has two congruent, polygon-shaped bases, and other faces that are all rectangles |
protractor | A tool used for measuring or drawing angles |
pyramid | A solid figure with a polygon base and all other faces triangles that meet at a common vertex |
quadrilateral | A polygon with four sides |
radius | A line segment with one endpoint at the center of a circle and the other endpoint on the circle |
ray | A part of a line, with one endpoint, that continues without end in one direction |
rectangle | A parallelogram with four right angles |
rectangular prism | A solid figure in which all six faces are rectangles |
reflection (flip) | A movement of a figure to a new position by flipping it over a line |
regular polygon | A polygon in which all sides are congruent and all angles are congruent |
rhombus | A parallelogram with four congruent sides |
right angle | An angle formed by perpendicular lines, line segments, or rays and with a measure of 90° |
right triangle | A triangle with one right angle |
rotation (turn) | A movement of a figure by turning it around a fixed point |
rotational symmetry | The property of a figure that can be rotated less than 360° around a central point and still be congruent to the original figure |
scale drawing | A drawing that shows a real object smaller than (a reduction) or larger than (an enlargement) the real object |
scalene triangle | A triangle with no congruent sides |
similar figures | Figures with the same shape but not necessarily the same size |
solid figure | A three-dimensional figure |
pi | The ratio of the circumference of a circle to its diameter |
sphere | A solid figure that has the shape of a round ball; all points are the same distance from the center |
square | A rectangle with 4 equal sides |
square pyramid | A pyramid with a square base and four triangular faces |
tangram | A puzzle consisting of seven polygon-shaped pieces that can be rearranged to make various figures or shapes |
tessellation | An arrangement of closed figures that completely covers a surface with no gaps and no overlaps |
three-dimensional | Measured in three directions, such as length, width, and height |
transformation | The movement of a figure by a translation, reflection, or rotation |