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Whitney Geometry
Question | Answer |
---|---|
acute triangle | A triangle in which all three angles are acute Examples: |
angle | A figure formed by two rays that have a common endpoint Example: |
chord | A line segment with its endpoints on a circle Example: |
circle | A closed plane figure with all points on the figure the same distance from the center Example: |
circumference | The distance around a circle Example: |
closed figure | A figure that begins and ends at the same point Examples: |
cone | A solid figure that has a circular base and one vertex Examples: |
congruent | Having the same size and shape Example: The triangles are congruent. |
congruent figures | Figures that have the same size and shape Example: The triangles are congruent. |
coordinate plane | A plane formed by two intersecting and perpendicular number lines called axes Example: |
coordinates | The numbers in an ordered pair Example: |
cube | A solid figure with six congruent square faces Examples: |
cylinder | A solid figure that has two parallel bases that are congruent circles Examples: |
degree (°) | A unit for measuring angles and temperature Examples: |
diamete | A line segment that passes through the center of a circle and has its endpoints on the circle Example: diameter |
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 Example: edge |
equilateral triangle | A triangle with three congruent sides Example: |
face | A polygon that is a flat surface of a solid figure Example: face |
figurate numbers | Numbers that can be represented by geometric figures Examples: |
hexagon | A polygon with six sides and six angles Examples: |
hypotenuse | In a right triangle, the side opposite the right angle; the longest side in a right triangle Example: hypotenuse |
intersecting lines | Lines that cross at exactly one point Example: Line EF intersects line GH. |
isosceles triangle | A triangle with two congruent sides Example: |
line | A straight path in a plane that goes on forever in opposite directions Example: line AB or line BA |
line segment | A part of a line that includes two points, called endpoints, and all of the points between them Example: line segment AB or line segment BA |
line symmetry | A figure has line symmetry if a line can separate the figure into two congruent parts Example: |
obtuse angle | An angle whose measure is greater than 90° and less than 180° Example: |
obtuse triangle | A triangle that has one obtuse angle Example: |
octagon | A polygon with eight sides Examples: |
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 Example: (1,2) represents 1 unit to the right of zero and 2 units up. |
parallel lines | Lines in a plane that never intersect Example: |
parallelogram | A quadrilateral whose opposite sides are parallel and congruent Examples: |
pentagon | A polygon with five sides Examples: |
perpendicular lines | Two lines that intersect to form four right angles Example: |
(noun) | The ratio of the circumference of a circle to its diameter An approximate decimal value of pi is 3.14. |
plane | A flat surface that extends without end in all directions Example: Planes are named by three points in the plane |
plane figure | A figure which lies in a plane Examples: |
point | An exact location in space, usually represented by a dot Example: point A |
When a figure can be turned half way about a central point and still look the same Example: | |
polygon | A closed plane figure formed by three or more line segments Examples: |
polyhedron | A solid figure with flat faces that are polygons Examples: |
prism | A solid figure that has two congruent, polygon-shaped bases, and other faces that are all rectangles Examples: rectangular prism triangular prism |
protractor | A tool used for measuring or drawing anglesExample: |
pyramid | A solid figure with a polygon base and all other faces triangles that meet at a common vertex Example: This is a square pyramid. |
quadrilateral | A polygon with four sides Examples: |
radius | A line segment with one endpoint at the center of a circle and the other endpoint on the circle Example: radius |
ray | A part of a line, with one endpoint, that continues without end in one direction Example: ray CD |
rectangle | A parallelogram with four right angles Example: |
rectangular prism | A solid figure in which all six faces are rectangles Example: |
reflection (flip) | A movement of a figure to a new position by flipping it over a line Example: |
regular polygon | A polygon in which all sides are congruent and all angles are congruent Examples: |
rhombus | A parallelogram with four congruent sides Example: |
right angle | An angle formed by perpendicular lines, line segments, or rays and with a measure of 90° Example: |
right triangle | A triangle with one right angle Example: |
rotation (turn) | A movement of a figure by turning it around a fixed point Example: |
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 Example: |
scale drawing | A drawing that shows a real object smaller than (a reduction) or larger than (an enlargement) the real object Example: |
scalene triangle | A triangle with no congruent sides Example: |
similar figures | Figures with the same shape but not necessarily the same size Example: |
solid figure | A three-dimensional figure Examples: sphere cube |
sphere | A solid figure that has the shape of a round ball; all points are the same distance from the center Example: |
square | A rectangle with 4 equal sides Example: |
square pyramid | A pyramid with a square base and four triangular faces Example: |
tangram | A puzzle consisting of seven polygon-shaped pieces that can be rearranged to make various figures or shapes Example: |
tessellation | An arrangement of closed figures that completely covers a surface with no gaps and no overlaps Example: |
three-dimensional | Measured in three directions, such as length, width, and height Example: heightwidth lengthThe rectangular prism is a three-dimensional figure. |
transformation | The movement of a figure by a translation, reflection, or rotation Examples: translationreflectionrotation |
translation (slide) | A movement of a figure along a straight line Example: |
trapezoid | A quadrilateral with one pair of parallel sides Examples: |
triangle | A polygon with three sides Examples: |
triangular number | A number that can be represented by a triangular array Examples: |
two-dimensional | Measured in two directions, such as length and width Example: widthlength |
vertex | The point where two or more rays meet; the point of intersection of two sides of a polygon; the point of intersection of three or more edges of a solid figure; the top point of a cone; the plural of vertex is vertices Examples: |
volume | The measure of the amount of space a solid figure occupies Example: The volume of this figure is 24 cubic units |
x-axis | The horizontal number line on a coordinate plane Example: |
x-coordinate | The first number in an ordered pair, which tells the distance to move right or left from (0, 0) Example: |
y-axis | The vertical number line on a coordinate plane Example: |
y-coordinate | The second number in an ordered pair, it tells the distance to move up or down from (0, 0) Example: |
Circumference | C = x d |
Volume of rectangular prism | V = l x w x h |
Perimeter of polygon | = sum of lengths of sides |
Perimeter of rectangle | P = (2 x l) + (2 x w) |
Perimeter of square | P = 4 x s |
Area of rectangle | A = l x w |
Area of parallelogram | A = bh |
Area of triangle | A = bh |