Lesson 4: 1.4 Basic Constructions
Duration of Days: 3
Lesson Objective
Construct perpendicular bisectors and copy angles
How does a compass help us ensure perfect measurements and symmetry?
Construct
Compass
Bisector
Perpendicular
CCSS.G.CO.D.12
I DO: Model using a compass on the whiteboard to draw a perfect circle and bisect a line.
WE DO: Paper folding activity (patty paper) to physically fold a line segment in half to find the perpendicular bisector without tools first.
YOU DO: Use a compass and straightedge to independently construct 3 perpendicular bisectors and copy an angle.
Develop fine motor skills and an understanding of precision drafting tools.
DOK 2 (Skill/Concept)
Support (Low): Provide step-by-step guided templates with pre-drawn starting points.
Extension (High): Have students freehand construct a square using only a compass and straightedge.
Formative Assessment
Drafting compasses and straightedges
Patty paper (tracing paper)
Desmos geometry tools