Geometric elements (1)
-
Upload
elena-lopez-ripoll -
Category
Education
-
view
675 -
download
2
Transcript of Geometric elements (1)
GEOMETRIC ELEMENTS
POLYGONESCIRCLE
ANGLES
LINES
POINTS
POINTS
• We may think of a point as a “dot” on a piece of paper.
• We identify this point with a number or a CAPITAL letter.
• A point has no length or width, it just specifies an exact location.
ACTIVITY 1
Look this
picture and
create one
using only
points.
LINES• STRAIGHT LINES don’t have a begginig or an
end.• RAYS has a beginning point but it hasn’t an
end point.• LINE SEGMENT has a beginning point and an
end point.• CURVE LINES• POLYGONAL LINES• PARALLEL LINES• SECANT STRAIGHT LINES• PERPENDICULAR LINES
ACTIVITY 2• USING YOUR SQUARE AND YOUR TRIANGLE
(RULES), DRAW LINES
ANGLES
• Two rays that share the same endpoint, called vertex.
• Clasification by measurement:– Acute<90º– Right =90º– Obtuse>90º– Flat =180º– Full =360º
• We use the protactor.
ANGLES
• ANGLE BISECTOR is a ray that divides an angle into two equal angles.– Place the compasses' point on the angle's vertex.– Adjust the compasses to a medium wide setting. The exact width
is not important. – Without changing the compasses' width, draw an arc across
each leg of the angle. – Place the compasses on the point where one arc crosses a leg
and draw an arc in the interior of the angle. – Without changing the compasses setting repeat for the other leg
so that the two arcs cross. – Using a straightedge or ruler, draw a line from the vertex to the
point where the arcs cross
How to make it
ACTIVITY 3 and 4
• Use the protactor and clasify the angles.
• Draw angles.
• Draw the angle bisector.
POLYGONS
• A polygon is a closed figure made by joining line segments.
• Polygons can be regular or irregular; o, .– Triangles (3 sides)– Quadrilateral (4 sides)– Pentagon (5 sides)– Hexagon (6 sides)– Heptagon (7 sides)– …
ACTIVITY
• Using polygons, draw yourself.
CIRCLE
• Radius: it’s the distance from the center of the circle to the outside edge.
• Diameter: it’s the longest distance across a circle.
• Circumference: it’s the perimeter, the distance around the outer edge.
• Chord: it’s a line segment that connects one point on the edge of the circle with another point on the circle.
• Arc: it’s a segment of the circumference of the circle.
• Sector: it’s a pie shaped portion of the área of the circle.
ACTIVITY
• Draw a circle using the compass (12 cm of diameter)
• Write the parts of the circle and the circumference.
• Calculate the circumference 2xπxr2