Circle information
Do radius and diameter have a proportional relationship? If so, what is it?
yes, 2
What does circumference mean?
the distance around a circle (like perimeter of square)
What is the equation for the area of a circle?
A = pi x r x r
what is the area of a circle with a 2.4 cm radius? (to the nearest tenth)
A=3.14x 2.4 x2.4 A=18.1cm^2
If the radius is 10 inches what is the diameter
20 inches
What is circumference divided by (diameter)?
Pi
What is the equation for circumference?
c=pi x d
If you have a circular mirror with a radius of 20cm, what is its area?
A= π x 20x 20cm A = 400π cm2
true or false: If the radius of a circle is doubled, then the circumference is also doubled?
Always true
If the circumference is 220 ft what is the radius? (rounded to the nearest hundredth)
35.03 ft
What is circumference divided by (radius)?
2pi
A circle has a diameter of 25cm. What is it's area?(2 decimal places)
r=12.5cm
A=π x 12.5 x 12.5
= 490.63cm2
Is Pi irrational? (meaning it doesn't stop)
yes
The circumference of a circle is 78.5 inches what is the area of the circle
radius 12.5
area = 12.5*12.5* 3.14
490.625 inches squared
What are the equations for finding the radius and diameter?
radius= d ÷ 2 diameter =r x 2
If you are given a radius of 6cm, what is the circumference?
12π cm
The area of a circle is about how many times the square of its radius? a.1 b.2 c.3 d.4
answer: 3
The measure of space covered by a 2-D shape is the definition for what? And Find this if you have a radius of 5cm.
area =78.5 cm^2
What is the area of a quarter circle with a radius of 10ft ?
78.5 ft squared
What is the radius of a circle with a diameter of 95m? (leave your answer in cm)
4750 cm
What is the diameter of a circle that has a circumference of 221mm? (round to nearest hundredth)
c= π x d 221mm = 3.14 x d 221/3.14 =d d=70.38mm
Fourty-four metres of fencing is used to make a circular enclosure. What is the area of the circle? (to the nearest square metre)
44 is the circumference
44=3.14 x d 14.01= d r=7.01 A= π x r x r A= 3.14 x 7.01 x 7.01 A=154 m2
is area and circumference proportional?
NO
What is the area of a half circle with a diameter of 18 cm
127.17