Thread: Circle's Diameter

If the circumference of a circle is doubled, the diameter of the circle

(1) remains the same
(2) increases by 2
(3) is multiplied by 4
(4) is doubled

Originally Posted by symmetry

If the circumference of a circle is doubled, the diameter of the circle

(1) remains the same
(2) increases by 2
(3) is multiplied by 4
(4) is doubled

Is doubled.


Thus,

If the circumference of a circle is 12, the the diameter = pi(12)(d), right?

What whatever the circumference equals, the diameter increases by the same amount, right?

Originally Posted by symmetry

If the circumference of a circle is 12, the the diameter = pi(12)(d), right?

What whatever the circumference equals, the diameter increases by the same amount, right?

Right

Originally Posted by symmetry

If the circumference of a circle is 12, the the diameter = pi(12)(d), right?...

Hello,

you know already that the circumference of a circle is calculated by:

, with diameter = 2 * radius.

Plug in the value you know:

.

In general:



EB

PS: I've attached a diagram which helps to memorize the right formula: Cover the variable you want to calculate with your fingertip. The remaining term shows how to calculate the covered value.

Thank you for the notes and reply.

Earboth,

Thank you for the picture. I think tutors should use pictures here to help students.