4.1 Investigating Circles

Focus: Measure both the radius and the diameter and
discover their relationship.

A circle is an enclosed curve.
All points on a circle are the same distance from the center of the circle.
A radius represents the distance from the circle center to the circle's edge.
radii is the plural form of radius.
A diameter is any line from 1 side of the circle, to the other......but must pass through the center of the circle.
2 radii equal 1 diameter. (2r = 1d)

Explore - p. 130

A. Construct a Circle with a radius of 4 cm. Label
the radius, and explain how you made the circle.
B. Construct a circle with a diameter of 7 cm.
Label your circle and explain it's construction.
C. Construct a circle with a radius of 10 cm. Do
not use a compass. Explain your strategy.
D. Construct a circle, but do not mark the circle
centre. Cut out the circle. Explain how you
could find the circle's centre.

Complete homework
page...131

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