Radius
If the diameter is 20cm, what is the RADIUS?
10
A radius circle is 5. What is its diameter?
10
Point in the middle of the circle
Center
A round pizza has a radius of 5 inches. What is the area of the pizza?
A=3.14(r)(r)
A= 3.14 (5)(5)
A=79in2
What is Circumference?
Distance AROUND
If the diameter is 100 cm, what is the radius
50 cm
The radius is 6 meters; what is its diameter
12 meters
Measuring the outside of the circle
Circumference
If the radius of a circular garden is 4 meters, what is the area of the garden?
A= 3.14 (r)(r)
A= 3.14 (4)(4)
A= 50m 2
A circle has a radius of 3 cm. What is the circumference of the circle?
C=2(3.14)(3)
C= 18.84cm or 19cm
What is the formula used to find the radius?
r = d/2
What is the formula to find the diameter?
d= r2
Half of the diameter
Radius
What is the formula to find the area?
A = Pi r 2 or A= 3.14 (r) (r)
Formulas to find Circumference
C= 3.14d
C=2(3.14)(r)
If the diameter is 350, what is its radius
175
If the radius is 45 cm, what is the diameter
90 cm
How do you find area and perimeter of a square
Area:
A= L x W
Perimeter:
P= L+L+W+W or 2l +2w
The radius of a circular swimming pool is 2 feet. What is the area of the swimming pool?
A= 3.14 ( 2)(2)
A=12ft2
A round pizza has a radius of 5 inches. What is the circumference of the pizza?
C=2(3.14)(5)
C=31.4in or 31in
If the diameter is 80 inches, what is its radius
40 inches
If the radius is 30ft, what is the DIAMETER?
60 ft
A straight line segment that passes through the circle's center and whose endpoints lie on the circle.
diameter
A circle has a radius of 7 cm. What is the area of the circle?
A=3.14(7)2
154cm2
A circular swimming pool has a radius of 7 feet. What is the circumference of the swimming pool?
C=2(3.14)(7)
C=43.96 ft or 44ft