## Unit 1 - Naming & Constructing Geometric Figures

**Internet Connections**

*Congruent Triangles*- This manipulative allows you to construct two triangles from various combinations of sides and angles. You can choose to work with any one of four different cases.

*Angle Sums*- Examine the angles in a triangle, quadrilateral, pentagon, hexagon, heptagon or octagon. Can you find a relationship between the number of sides and the sum of the interior angles?

**Recognizing Student Achievement**

Student’s are making adequate progress if they can demonstrate the following:

• automaticity with addition & subtraction facts

• explain the difference between a line and a line segment

• explain how two quadrangles are alike and different

• draw and name quadrangles with 2 pairs and 1 pair of parallel sides

• describe the properties of polygons

• draw a polygon with a right angle

• draw concentric circles

**Vocabulary**

**angle**- A figure formed by two rays or line segments with a common endpoint. The common endpoint is called the vertex. Angles are measure in degrees. An acute angle measures less than 90°. An obtuseangle measures more than 90° but less than 180°. A right angle measures 90°.

**circle**- The set of all points the same distance from a fixed point. The fixed point is called the center of the circle. The distance from the center to the circle is called the radius.

**concave polygon**- A polygon in which at least one vertex is “pushed” or “caved in.”

**concentric circles**- Two or more circles with the same center but with radii of different lengths.

**congruent**- Having the same shape and size.

**convex polygon**- A polygon in which all vertices are “pointed out.”

**endpoint**- A point at the end of a line segment or ray.

**equilateral triangle**- A triangle with three equal sides and three equal angles. A type of regular polygon.

**intersect**- To meet or cross.

**kite**- A quadrangle with zero pairs of parallel sides. Equal sides are next to each other. The four sides cannot all have the same length, so a rhombus is not a kite.

**line**- A straight path that extends infinitely in opposite directions.

**line segment**- A straight path joining two points. The points are called endpoints.

**parallel**- Lines, line segments, or rays that never meet or cross, no matter how far they are extended.

**parallelogram**- A quadrangle with two pairs of parallel sides.

**pentagon**- A five-sided polygon.

**perpendicular**- Crossing or meeting at right angles.

**point**- An exact location in space.

**polygon**- A 2-dimensional figure that is made up of three or more line segments joined end to end to make a closed path. The line segments of a polygon may not cross.

**quadrangle**- A polygon with four angles. Same as quadrilateral.

**radius**- A line segment from the center of a circle (or sphere) to any point on the circle (or sphere).

**rectangle**-A parallelogram with 4 right angles.

**regular polygon**- A polygon with all equal sides and angles.

**rhombus**- A quadrilateral whose sides are all the same length. All rhombuses are parallelograms. Every square is a rhombus, but not all rhombuses are squares.

**right angle**-An angle measuring 90°. Also called a square corner.

**square**- A rectangle whose sides are all the same length.

**trapezoid**- A quadrilateral with exactly one pair of parallel sides.

**triangle**- A 3-sided polygon.

**vertex (vertices)**- The point where the sides of an angle, the sides of a polygon, or the edges of a polyhedron meet.