Geometry Vocab

Stephanie Jimenez

Angle

• The union of two rays having a common endpoint, the rays are the sides of the angle and the common endpoint is the vertex

Dodecagon 24.08.2009

• A polygon having twelve sides• A dodecagon has twelve sides.

Scalene Triangle 25.08.2009• Triangle having no sides of the same length• They are three kinds of triangles: isosceles,

scalene and…….. equal triangle.

Concentric Circles 26.08.2009• Circles having the same center but with

different radii• Many concentric circles have a different radii.

Postulate 27.08.2009

• A statement accepted as true without having to be proven to be true

• He postulated that the circle was round.

Hypotenuse 31.08.09

• The side opposite the right angle in a right triangle: the longest side of a right triangle

Compass 1.09.09

• A construction tool used to draw arcs and circles

Circle 3.09.09

• The set of all points in a plane that are equidistant from a given point known as the center of the circle

• (x-h)2 + (y-k)2 =r2

Acute Angle

• An angle having a measure greater that 0 degrees but less then 90 degrees

Complementary Angles 9.9.09

• Two angles whose sum equals 90 degrees

Diameter 9.10.09

• A chord that passes through the center of a circle

Parallel Lines 11.09.09

• Coplanar lines that do not intersect

Polygon 14.09.09

• A plane figure bounded by a number of line segments; the minimum number of sides is 3

Theorem 15.09.09

• A statement in math which must be proven to true

Adjacent Angles 17.09.09

• Two angles having a common side and vertex but do not overlap; no common interior points

Orthogonal 18.09.09

• Intersecting of right angles

Hemisphere 21.09.09

• the surface bounded by half of a sphere and a plane through the center of the sphere

Incenter 23.09.09

• the point of concurrency of the triangle’s angle bisectors

KITE 24.09.09

• a quadrilateral in which two disjoint pairs of consecutive sides are congruent

Collinear 25.09.09

• points that lie on the same line

• A collinear line has points in it.

Skew Lines 29.09.09

• lines that do nor intersect and are not coplanar

Perpendicular Lines 30.09.09

• lines that intersect at right angles

Transversal 01.10.09

• a line which intersects two or more coplanar lines in distinct points

Obtuse Angle 02.10.09

• an angle having a measure greater than 90 degrees but les than 180 degrees

Prism 05.10.09

• a polyhedron with two congruent faces, called bases, that lie in parallel planes; the other faces are called lateral faces

Proof 06.10.09

• a convincing argument that shows why a statement is true

Slant Height 08.10.09

• the height of a lateral face of a pyramid• the mouse ran up the slant height of the grain

pile

Circumference 09.10.09

• the distance around a circle

Straightedge 12.10.09

• a construction tool used to draw segments: a ruler without marks

Inscribed Angle 13.10.09

• an angle of a circle having its vertex on the circle and the sides of the angle are chords of the circle

Isosceles Triangle 14.10.09

• a triangle with at least two congruent sides; equilateral triangles are isosceles

Hypothesis 15.10.09

• the phrase following the word “if” in a conditional statement

Octagon 16.10.09

• a polygon having eight sides

• A stop sign is an octagon.

Logic 19.10.09

• the analysis of the patterns of reasoning by which conclusions are validly derived from sets of premises

Similar Figures 20.10.09

• figures that have the same shape

• Similar figures have the same shape.

Angle of depression 21.10.09

• an angle formed by a horizontal line and the line of sight to an object below the level of the horizontal

Rhombus 10.22.09

• a quadrilateral with four equal sides

• A kite is a rhombus.

Rectangle 10.23.09

• parallelogram with 4 right angles

• We found the area of the rectangle in class.

Deductive Reasoning 26.10.09

• a process of reasoning logically from given facts to a conclusion

Sector 27.10.09

• a region of a circle determined by two radii and a part of the circle

Translation 28.10.09

• a transformation that moves points the same distance and in the same direction; a slide

Heptagon 2.11.09

• a polygon having seven sides

Interior Angle 3.11.09

• An angle whose sides are determined by two consecutive sides of a polygon

Midpoint 4.11.09

• A point that divides a segment or an arc into two congruent parts

Arc 5.11.09

• A figure consisting of two points on a circle and all points on the circle needed to connect them to a single part

• A part of a circle

Apothem 6.11.09

• A segment joining the center of a regular polygon to the midpoint of one of the polygon’s sides

Tangent 9.11.09

• A line that intersects a circle at exactly one point

Frustum 10.11.09

• The part of a solid cone or pyramid formed by cutting off the top by a plane parallel to the base

Acute Triangle 11.11.09

• A triangle having three acute angles

Corollary 13.11.09

• A statement that follows directly from another theorem and that can easily be proved from that theorem to be true