1-6 Basic Constructions
Objective
To make basic constructions using a straightedge and a compass
Lesson Vocabulary
- straightedge
- compass
- construction
- perpendicular lines
- perpendicular bisector
In this lesson, you will learn another way to construct figures like the one above.
Essential Understanding You can use special geometric tools to make a figure that is congruent to an original figure without measuring. This method is more accurate than sketching and drawing.
A straightedge is a ruler with no markings on it. A compass is a geometric tool used to draw circles and parts of circles called arcs. A construction is a geometric figure drawn using a straightedge and a compass.
Problem 1 Constructing Congruent Segments
Construct a segment congruent to a given segment.
Given:
Construct:
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Step 1 Draw a ray with endpoint C.
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Step 2 Open the compass to the length of
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Step 3 With the same compass setting, put the compass point on point C. Draw an arc that intersects the ray. Label the point of intersection D.
Think
Why must the compass setting stay the same?
Using the same compass setting keeps segments congruent. It guarantees that the lengths of
✓ Got It?
- Use a straightedge to draw
Table of Contents
- 6-1 The Polygon Angle-Sum Theorems
- 6-2 Properties of Parallelograms
- 6-3 Proving That a Quadrilateral Is a Parallelogram
- 6-4 Properties of Rhombuses, Rectangles, and Squares
- 6-5 Conditions for Rhombuses, Rectangles, and Squares
- 6-6 Trapezoids and Kites
- 6-7 Polygons in the Coordinate Plane
- 6-8 and 6-9 Coordinate Geometry and Coordinate Proofs