Parts of a Circle
This can be found by multiplying the radius by 2.
What is the diameter?
This is the radius when the diameter is 9.
What is 4.5?
This strategy helps us visualize the r2 element of the equation for area of a circle.
What are radius squares?
Billy and Bobby are playing tug of war over a nearly circular lake with a circumference of 7π. This is the length of the rope.
What is 7?
r=3 units
d=6 units
c=3π units
a=9π units2
What is c=3π (c=6π)
This can be found by multiplying diameter and π (pi)
What is Circumference?
This is a formula to find circumference.
What is dπ (diameter x pi)?
What is 2πr (radius x 2 x pi)
This is the equation used to find area of a circle.
What is πr2?
What is r⋅r⋅π?
Sam is going on a drive around Waukesha (nearly a circle). From the center of town to LPP is 1.61 km. This is the distance Sam drives on his lap around Waukesha.
What is 2.33πkm?
What is 7.32km?
r=5.2
d=5.2
c=5.2π
a=6.76π
What is r=5.2 (r=2.6)
Susie gets on a horse on a carousel and rides around for one lap.
What is the Circumference?
This is the circumference when the radius is 8.
What is 16π?
What is 50.24?
This is the area of a circle with a radius of 5.
What is 25π?
What is 78.5?
Rudy is building a rabbit enclosure using 6 3-feet pieces of fence connected in the shape of a circle. This is the diameter of the enclosure.
What is 18/π?
What is 5.73?
r=10 meters
d=10⋅2 meters
c=10⋅2⋅π meters
a=10⋅π⋅π meters2
What is a=10⋅π⋅π (a=10⋅10⋅π)
This is the length from the tip of a slice of pizza to the crust.
What is the radius?
This is the diameter when the circumference is about 18.84cm.
What is 6cm?
This is the area of a circle when the diameter is 6.
What is 9π?
What is 28.26?
Laurie made a chocolate cake with a radius of 4. She cut it into 8 pieces. This is the area of one slice of cake. (2D)
What is 2π?
What is 6.28?
r=7.5 km
d=15 km
c=47.1 km
a=70.65 km2
What is a=70.65 (a=56.25π, 176.63)
The city park is nearly circular. Timmy takes a shortcut straight across the park passing the fountain in the center.
What is the diameter?
This is the radius when the circumference is 24π.
What is 12?
This is the area of a circle when the circumference is 8π.
What is 16π?
What is 50.24?
Clarisse is making donuts for her bakery. The area of a filled donut is 9π. The hole of non-filled donuts starts .5 inches from the edge of the donut. This is the area of the donut's hole. (2D)
What is 6.25π?
What is 16.63?
Area=9π. Radius=3. Diameter=6. -.5 -.5, Diameter of hole is 5. Radius is 2.5. Area is 6.25π.
r=15in
d=30in
c=188.4in
a=706.5in2
c=188.4in (94.2in)