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Help with math?

If anyone could be kind enough to explain this to me i would be much obliged.

AB is a chord of a circle and is 8cm long.

The centre, O, is 6cm from the mid-point of AB.

Calculate the length of the diameter of the circle.
Construct a triangle and find the hypotenuse by Pythagoras. That's your radius then double it to get the diameter.
Original post by Riddle2001
If anyone could be kind enough to explain this to me i would be much obliged.

AB is a chord of a circle and is 8cm long.

The centre, O, is 6cm from the mid-point of AB.

Calculate the length of the diameter of the circle.


Is there anyway you could use a diagram to show the lengths you know which might help you find relevant info
Original post by Riddle2001
If anyone could be kind enough to explain this to me i would be much obliged.

AB is a chord of a circle and is 8cm long.

The centre, O, is 6cm from the mid-point of AB.

Calculate the length of the diameter of the circle.


sketch sketch sketch, it'll be obvious once you've drawn it :smile:
Original post by Riddle2001
If anyone could be kind enough to explain this to me i would be much obliged.

AB is a chord of a circle and is 8cm long.

The centre, O, is 6cm from the mid-point of AB.

Calculate the length of the diameter of the circle.

Let the midpoint be M, so AM=4 and MO=6. Clearly angle AMO is a right angle. Thus by Pythagoras, AO=sqrt(16+36)=2sqrt(13). Thus the radius is 2root13, so the diameter is 4root13.
Original post by Riddle2001
If anyone could be kind enough to explain this to me i would be much obliged.

AB is a chord of a circle and is 8cm long.

The centre, O, is 6cm from the mid-point of AB.

Calculate the length of the diameter of the circle.


Lamo. Just make a triangle and use the formula A^2+B^2=C^2, that'll be your radius*2=diameter (this step tends to get allot easier when you have a diagram infront of you). The final step is to get high on potnuse. :smile:
(edited 8 years ago)

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