Circle information
What is the distance called that stretches the inside width of the circle, crossing through the center?
Diameter
What does circumference mean?
the distance around a circle
What is the equation for the area of a circle?
A = pi x r x r
How much should all the percents in a circle graph add up to?
100%
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 squared
What is the distance from the center of the circle to the outer edge called?
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 = 1256 cm2
If a class has 30 students and 40% of them have blonde hair, how many students have blonde hair?
12 students have blonde hair
true or false: If the radius of a circle is doubled, then the circumference is also doubled?
Always true
What is the equation for finding the diameter if you know radius?
2 x r
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
Which information could be in a circle graph?
1) white- 78%, pink 33%, brown 28%, red 42%
2) white 24%, pink 33%, brown 33%, red 29%
3) white 20%, pink 28%, brown 44%, red 8%
Number three can be a circle graph.
How many times longer is the circumference of a circle than the diameter?
3.14 (pi)
What is the equation for finding the radius if you know the diameter?
radius= d ÷ 2
If you are given a radius of 6cm, what is the circumference?
37.68cm
The area of a circle is about how many times the radius squared? a.1 b.2 c.3 d.4
answer: 3
There are 22 bouncy balls 8 are blue, 10 are red, and 4 are yellow. What is the percent of the BLUE bouncy balls?
8/22 = .36 which is 36 %.
What is the measure of space covered by a 2-D shape?
And find this if you have a radius of 5cm.
area =78.5 cm squared
What is the radius of a circle with a diameter of 95m?
47.5 m
What is the circumference of a circle that has a radius of 132 mm? (round to nearest hundredth)
d = 132 x 2 = 264 mm
c= pi x d
c = 3.14 x 264 = 828.96 mm
14 metres of fencing is used to separate a circular enclosure in half. What is the area of the circle? (to the nearest square metre)
r = 14/2 = 7
A = pi x r x r
A = 3.14 x 7 x 7
A = 154 meters squared
There are 30 students in the class. 3 people use the internet once a week, 9 people use the internet three times a week, 18 people use the internet every day. Draw the circle graph for internet usage in the class. Include percents for each category on this circle graph.
3- 10%, 9- 30%, 18- 60%
The outer ring of the Canadian toonie has an outside diameter of 28mm and an inside diameter of 8mm. What is the area of the outer ring to the nearest tenth of a square millimeter?
414.48mm squared