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Maths year 11

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That's wrong. If you want to convert it into cm, then rather than multiplying it by 100, you must multiply it by (100)3 because it's in 3 dimensions, therefore 100 per side.

You can check this by turning each side into cm FIRST before multiplying them all together. It would be the equivalent of
V=(2x100)x(2x100)x(2x100) where the 2's multiply by eachother 3 times as well as the 100s -> V=1003 x 23
(edited 7 years ago)
Original post by z_o_e
Yepp changed them to CM

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You can't convert volumes like that. All because there are 100cm in a meter does not mean that there are 100cm^3 in 1m^3.
Convert the side lengths of the container and work out the volume in cm^3 that way.
Reply 602
Original post by RDKGames
That's wrong. If you want to convert it into cm, then rather than multiplying it by 100, you must multiply it by (100)3 because it's in 3 dimensions, therefore 100 per side.

You can check this by turning each side into cm FIRST before multiplying them all together.




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Since the whole thing is a quarter of a circle with radius 4.8cm, you can work out that area to 3 s.f. Furthermore, you can work out the area of the triangle and take one away from the other to find the area of the segment.
Reply 606
Original post by RDKGames
Since the whole thing is a quarter of a circle with radius 4.8cm, you can work out that area to 3 s.f. Furthermore, you can work out the area of the triangle and take one away from the other to find the area of the segment.


How do I find the area of the triangle? :/

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Original post by z_o_e
How do I find the area of the triangle? :/

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Well the whole thing is a quarter of a circle; the key here is to realise that it means triangle's sides are both the radius of the circle.
Reply 608
Pi * 4.8 squared /2
?

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Reply 609
Original post by RDKGames
Well the whole thing is a quarter of a circle; the key here is to realise that it means triangle's sides are both the radius of the circle.


So I could do pi *4.8 squared /2?


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Original post by z_o_e
So I could do pi *4.8 squared /2?


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Not quite; what would that give you?
Reply 611
Original post by RDKGames
Not quite; what would that give you?


Area of the... semi circle?

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Original post by z_o_e
So I could do pi *4.8 squared /2?


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That would be the area of half of the circle you need 4.8π/4=1.2π 4.8\pi /4 = 1.2\pi . But you need to subtract the area of the triangle to get the shaded area of the minor segment.
Original post by z_o_e
Area of the... semi circle?

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Yes that would give you the semi-circle area, but you want a quarter of it.
Original post by B_9710
That would be the area of half of the circle you need 4.8π/4=1.2π 4.8\pi /4 = 1.2\pi . But you need to subtract the area of the triangle to get the shaded area of the minor segment.


That's not quite right...
Reply 615
Original post by RDKGames
Yes that would give you the semi-circle area, but you want a quarter of it.


I could divide that area in 2 to find a quarter.

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Original post by z_o_e
I could divide that area in 2 to find a quarter.

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Yep. Though you could've skipped this part by simply dividing the circle's area by 4 directly.
Reply 617
Original post by RDKGames
Yep. Though you could've skipped this part by simply dividing the circle's area by 4 directly.




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That's right. Now you can find the segment's area by taking away the triangle's area.
Reply 619
Original post by RDKGames
That's right. Now you can find the segment's area by taking away the triangle's area.


I didn't get this.

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