circles Flashcards
How do you find the perimeter of a circle?
radius x two x pi or
diameter x pi
what does it mean when it says in an exact answer?
radius by the power of two with the pi sign next to it
How do you find the perimeter of half a circle?
diameter divided by two, then times by pi then add the diameter. Example the diameter is 20
10 x pi + 20
How do you find the area of a circle using just the radius?
radius by the power of two then times it by pi.
E.g radius is 3
3 by the power of 2 is 9
9 x pi =area
how do you find the area of a circle using the diameter?
half the diameter. then use the power of two than times it by pi
E.g diameter is 20
divide by two =10
10 by the power of two
100 x pi = area
how do you find the area of a qauter circle?
radius by the power of two times pi divided by four
How do you find the area of a sector?
degrees of the sector divided by 360
times that by pi and then time by radies bhy the power of two
How do you find the volume of a rectangle?
radius by the power of two times hight times pi
E.g radius is 5
5 by the power of two is 25
25 x hight x pi
How do you find the volume of an inner cylinder?
pi x radius by the power of two x hight
What does an arc look like?
part of a cirle
lining of the circle on the outside which is a different colour
what is the diameter?
a line between the whole circle
what is the radius?
a line only reaching half the circle
what is a chord?
a line joining two parts of a cirlce
what’s a simecircle?
half a circle
what’s a segment?
when a chord is used there are minor and major segments
