# CollegeGeometry1.2

 The flashcards below were created by user clkottke on FreezingBlue Flashcards. intersection the points that two geometric figures share intuition drawing a conclusion through insight inverse relative to the statement “If P, then Q,” this statement has the form “If not P, then not Q” isosceles trapezoid a trapezoid that has two congruent legs(its nonparallel sides) isosceles triangle a triangle that has two congruent sides kite a quadrilateral that has two distinct pairs of congruent adjacent sides lateral area the sum of areas of the lateral faces of a solid orthe area of the curved lateral surface, excluding the base area(s) (as in prisms, pyramids, cylinders, and cones) legs of isosceles triangle the two congruent sides of the triangle legs of right triangle the two sides that form the right angle of the triangle legs of trapezoid the two nonparallel sides of the trapezoid lemma a theorem that is introduced and proved so that a later theorem can be proved line of centers the line (or line segment) that joins the centers of two circles line segment the part of a line determined by two points and all points on the line that lie between those two points locus the set of all points that satisfy a given condition or conditions octahedron (regular) a polyhedron with eight congruent faces that are equilateral triangles opposite rays two rays having a common end point and which together form a line orthocenter of triangle the point of concurrence for the three altitudes of the triangle parallel lines (planes) two lines in a plane (or two planes) that do not intersect parallelogram a quadrilateral that has two pairs of parallel sides parallelepiped a right rectangular prism; a box pentagon a polygon that has exactly five sides perimeter of polygon the sum of the lengths of the sides of the polygon perpendicular bisector of line segment a line (or part of aline) that is both perpendicular to a given line segment and bisects that line segment perpendicular lines two lines that intersect to form congruent adjacent angles pi ( ) the constant ratio of the circumference C of a circle to the length of its diameter, this ratio is commonly approximated by the fraction or the decimal 3.1416 point of tangency (contact) the point at which a tangent to a circle touches the circle polygon a plane figure whose sides are line segments that intersect only at their endpoints polyhedron a solid figure whose faces are polygons that intersect other faces along common sides of the polygons postulate a statement that is assumed to be true Quadratic Formula the formula ,which provides solutions for the equation ,where a, b, and c are real numbers and quadrilateral a polygon that has exactly four sides radian the measure of a central angle of a circle whose intercepted arc has a length equal to the radius of the circle radius the line segment that joins the center of a circle (or sphere) to any point on the circle (or sphere) ratio a comparison between two quantities , generally written or a:b ray the part of a line that begins at a point and extends infinitely far in one direction rectangle a parallelogram that contains a right anglereflex angle an angle whose measure is between 180°and 360° regular polygon a polygon whose sides are congruent and whose interior angles are congruent regular polyhedron a polyhedron whose edges are congruent and whose faces are congruent major arc an arc whose measure is between 180° and 360° means of a proportion the second and third terms of a proportion; in , b and c are the means median of trapezoid the line segment that joins the midpoints of the two legs (nonparallel sides) of the trapezoid median of triangle the line segment joining a vertex of the triangle to the midpoint of the opposite side midpoint the point on a line segment (or arc) that separates the line segment (arc) into two congruent parts minor arc an arc whose measure is between 0° and 180° nonagon a polygon that has exactly nine sides noncollinear points three or more points that do not lie on the same line noncoplanar points four or more points that do not lie in the same plane obtuse angle an angle whose measure is between 90°and 180° obtuse triangle a triangle that has exactly one interior angle that is obtuse octagon a polygon that has exactly eight sides regular prism a right prism whose bases are regular polygons regular pyramid a pyramid whose base is a regular polygon and whose lateral faces are congruent isosceles triangles rhombus a parallelogram with two congruent adjacent sides right angle an angle whose measure is exactly 90° right circular cone a cone in which the line segment joining the vertex of the cone to the center of the circular base is perpendicular to the base right circular cylinder a cylinder in which the line segment joining the centers of the circular bases is perpendicular to the plane of each base right prism a prism in which lateral edges are perpendicular to the base edges that they intersect right triangle a triangle in which exactly one interior angle is a right angle scalene triangle a triangle in which no two sides are congruent secant in a right triangle, the ratio secant of circle a line (or part of a line) that intersects a circle at two points sector of circle the plane region bounded by two radii of the circle and the arc that is intercepted by the central angle formed by those radii segment of circle the plane region bounded by a chord and a minor arc (major arc) that has the same endpoints as that chord semicircle the arc of semicircle the arc of a circle determined by a diameter; an arc of a circle whose measure is exactly 180° set any collection of objects, numbers, or points similar polygons polygons that have the same shape sine in a right triangle, the ratio skew quadrilateral a quadrilateral whose sides do not all lie in one plane slant height of cone any line segment joining the vertex of the cone to a point on the circular base slant height of regular pyramid a line segment joining the vertex of the pyramid to the midpoint of a base edge of the pyramid slope a measure of the steepness of a line; in the rectangular coordinate system, the slope m of the line through (x1,y1) and (x2,y2) is , where x1 x2 sphere the set of points in space that are at a fixed distance from a given point (the center of the sphere) straight angle an angle whose measure is exactly 180°; an angle whose sides are opposite rays straightedge an idealized instrument used to construct parts of lines volume the measurement, in cubic units, of the amount of space within a bounded region of space vertical angles a pair of angles that lie in opposite positions when formed by two intersecting lines vertex of polyhedron any point at which three edges of the polyhedron meet vertex of polygon any point at which two sides of the polygon meet vertex of isosceles triangle the point at which the two congruent sides of the triangle meet vertex of angle the point at which the two sides of the angle meet vertex angle of isosceles triangle the angle formed by the two congruent sides of the triangle valid argument an argument in which the conclusion follows logically from previously stated (and accepted) premises or assumptions union the joining together of any two sets, such as geometric figures triangle inequality a statement that the sum of the lengths of two sides of a triangle cannot be greater than the length of the third side triangle a polygon that has exactly three sides trapezoid a quadrilateral having exactly two parallel sides transversal a line that intersects two or more lines, intersecting each at one point torus a three-dimensional solid that has a “doughnut” shape theorem a statement that follows logically from previous definitions and principles; a statement that can be proved tetrahedron (regular) a four-faced solid in which the faces are congruent equilateral triangles tangent line of circle a line (or part of a line) that touches acircle at only one point tangent circles two circles that have one point in common;the circles may be externally tangent or internally tangent tangent in a right triangle, the ratio symmetry with respect to a point (P ) figure for which everypoint A has a second point C on the figure for which P is the midpoint of symmetry with respect to a line (l) figure for which everypoint A has a second point B on the figure for which l is the perpendicular bisector of surface area the measure of the total area of a solid; the sum of the lateral area and base area in many solid figures. supplementary angles two angles whose sum of measuresis 180° Authorclkottke ID129099 Card SetCollegeGeometry1.2 DescriptionGeometry Vocabulary Updated2012-01-20T01:38:38Z Show Answers