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Circles. Circles are EVERYWHERE . VOCABULARY. Diameter Radius Circumference Pi. DIAMETER. Diameter is the distance through the middle of the circle. It is twice as large as the radius. d =diameter r= radius. Radius. Radius is ½ as large as the diameter. R=1/2d
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Circles Circles are EVERYWHERE.
VOCABULARY Diameter Radius Circumference Pi
DIAMETER Diameter is the distance through the middle of the circle. It is twice as large as the radius. d =diameter r= radius
Radius • Radius is ½ as large as the diameter. • R=1/2d • The radius is used in many circle formulas
PI IS NOT : • A whole pie • A slice of pie
PI • Pi is the ratio of the circumference to the diameter. This is the symbol for pi p
The diameter of the quarter is 5.5cm. What is the circumference?
AND THE ANSWER IS….. 17.27 cm
Circumference • Circumference is the distance around the circle. To find the circumference of a circle You have to know the diameter or radius.
Radius = 4cm Circumference = 2 X R X π Circumference= 2 X 4 X 3.14 C= 25.12 cm
Diameter = 10cm C= π x D C= 3.14 x 10 C= 31.4 cm
WHAT IS THE DIAMETER? Radius is 6 inches Diameter is 12 inches
LET’S PRACTICE D= 24 INCHES R= 12 inches