Yes, I know this is the urgent forum. The title means this is EXTRA urgent. As in, before 8 am on Thursday morning (today). I've been working on this math project all night, and there's a few things I'm really having trouble with. If anyone can help me with this, they will earn my eternal gratitude.

It is: A cone is formed from a circle of radius 10 cm with a sector of $\displaystyle 90^o$ cut out.

A) What is the slant height of the cone

B) What is the radius of the cone?

C) What is the volume of the cone, to the nearest cubic centimetre?

Ok, I know that "A" is 10 cm, because the slant height of a cone is equal to the radius of the circle it's formed from.

But what about "B"? I know I can't use the Pythagorean Theorem, because I only have slant height...

Once I know the radius, for C I should just be able to use the formula for volume.

There's my first question. here's the next.

There's a rectangular prism which has dimensions 4 by 5 by 10. There's also a rectangular prism which has dimensions three times those of the small box.

a) Compares the volume of the two boxes and explain your answer

b) compare the surface area of the boxes and compare your answer.

the volume of 4 by 5 by 10 is 200

The volume of 12 by 15 by 30 is 5400

I'm not really seeing a correlation... What am I missing?

And finally,

What happens to the volume of a cone under each set of conditions?

a) the radius is unchange but the height is doubled

b) the radius is doubled but the height is unchanged

c) The radius and the hieght are both doubled.

I'm really not sure how to do this one at all- all I know is "It gets bigger"

Your help is really, REALLY appreciated.