Geometry: A Year Around By: Kourtney Mansfield

Chapter 1: Points, Lines, and Planes Point – Has no dimension. Usually represented by a small dot. Point – Has no dimension. Usually represented by a small dot. Line – Extends in one dimension. Usually represented by a straight line with two arrow heads to indicate the line extends in two direction, without end. Line – Extends in one dimension. Usually represented by a straight line with two arrow heads to indicate the line extends in two direction, without end. Plane – Extends in two dimensions. Usually represented by a shape that looks like a tabletop or wall. Plane – Extends in two dimensions. Usually represented by a shape that looks like a tabletop or wall. Collinear Points – Points that lie on the same line. Collinear Points – Points that lie on the same line. Coplanar Points – Points that lie on the same plane. Coplanar Points – Points that lie on the same plane.

Chapter 3: Lines and Angles Parallel Lines – Coplanar lines that do not intersect. Skew Lines – Lines that do not intersect and are not coplanar. Parallel Planes – Two planes that do not intersect. Transversal – A line that intersects two or more coplanar lines at different points.

Chapter 4:Triangles and Angels Vertex – Each of the three points joining the sides of a triangle. Vertex – Each of the three points joining the sides of a triangle. Adjacent Sides – Two sides sharing a common vertex. Adjacent Sides – Two sides sharing a common vertex. Legs – The sides that form the right angle. Legs – The sides that form the right angle. Hypotenuse – The side opposite the right angle. Hypotenuse – The side opposite the right angle. Interior Angles – The three original angles. Interior Angles – The three original angles. Exterior Angles – The angles that are adjacent to the interior angles. Exterior Angles – The angles that are adjacent to the interior angles.

Chapter 6: Polygons Convex Polygon – If no line that contains a side of the polygon contains a point in the interior of the polygon. Convex Polygon – If no line that contains a side of the polygon contains a point in the interior of the polygon. Nonconvex or Concave Polygons– If a line that contains a side of the polygon contains a point in the interior of the polygon. Nonconvex or Concave Polygons– If a line that contains a side of the polygon contains a point in the interior of the polygon. Equilateral Polygon – All sides are congruent. Equilateral Polygon – All sides are congruent. Equiangular Polygon – All interior angles are congruent. Equiangular Polygon – All interior angles are congruent. Regular Polygon – Equilateral and equiangular. Regular Polygon – Equilateral and equiangular.

Chapter 7: Rigid Motion in a Plane and Reflections Preimage – The original figure. Preimage – The original figure. Image – The new figure. Image – The new figure. Transformation – The operation that moves the preimage onto the image. Transformation – The operation that moves the preimage onto the image. Reflection – Uses a line that acts like a mirror, with an image reflected in the line. Reflection – Uses a line that acts like a mirror, with an image reflected in the line. Line of Reflection – The mirror line. Line of Reflection – The mirror line.

Chapter 8: Ratio and Proportion Proportion – An equation that equates two ratios. Proportion – An equation that equates two ratios. Extremes – The numbers a and b in the proportion. Extremes – The numbers a and b in the proportion. Means – The numbers b and c in the proportion. Means – The numbers b and c in the proportion. Ratio – If a and b are two quantities that are measured in the same units, then the ration of a to b is a/b. Ratio – If a and b are two quantities that are measured in the same units, then the ration of a to b is a/b.

Chapter 9: Trigonometric Ratios Trigonometric Ratios – A ratio of the lengths of two sides of a right triangle. Sine, Cosine, and Tangent – The three basic trigonometric ratios. Angle of Elevation – The angle that your line of sight makes with a line drawn horizontally.

Chapter 10: Tangents to Circles Circle – The set of all points in a plane that are equidistant from a given point. Center – The given point located in the center of a circle. Radius – a segment whose endpoints are the center of the circle and a point on the circle. Diameter – The distance across the circle, through its center.

Chapter 11: Areas of Regular Polygons Center of the Polygon –The center of its circumscribed circle. Radius of the Polygon – The radius of its circumscribed circle. Apothem of the Polygon – The height of a triangle between the center and two consecutive vertices of the polygon.

Chapter 12: Surface Area of Prisms and Cylinders Prism – A polyhedron with two congruent faces. Bases – The two congruent faces of a prism. Lateral Faces – The other faces of a prism. Right Prism – Each lateral edge is perpendicular to both bases. Oblique Prisms – Prisms that have lateral edges that are not perpendicular to the bases.