Quote Originally Posted by SeeDRankLou
(This may take a while to type, so someone might post before me)

1. OK, a rectangle with a diagonal is 2 congruent right triangles on top of one another, right? Lets call the sides of the triangle 2a and 3a (the ratio, 2 of something to 3 of something), which are also two of the sides of the rectangle, and the side opposite the right angle is 26cm, the diagonal. Simple Pythagorean Theorem, (2a)^2 + (3a)^2 = 26^2. Work it out, a=52, so the sides are 104cm and 156cm, and thus the perimeter is 520cm.

2. Ok, a cube has all the same sides. Volume of a cube = length times width times height. Since those are all the same, well just call them all "a". So a^3 = 10cm^3. a = (cube root)(10)cm. There are 12 sides to a cube, so the sum of the lengths of the edges = 12(cube root)(10)cm. There are six sides to a cube. Each side of a cube is a square, and the area of a square = length times width, so the surface area of a cube = 6 times length time width. So surface area = 6a^2 = 6 x 10^(2/3)cm.
Grade: A

Quote Originally Posted by GooeyToast
Well if you posted the answer for number 1, I bet I could work out the answer and show you hjow I got it. Otherwise I've kinda forgotton how to do this

For #2, I CAN help you.

First, the vol of a cube is length times width times height right? But since all sides of a cube are equal, its just multiplying the same number 3 times.

So, 10 ^ 3 (which is really 1000) is just 10 times 10 times 10.

So, each side is 10 cm in length.

And since there's 12 edges on a cube, you just multiply 10 times 12 to get 120 cm, which is the total sum of the edges.

For SA, simply just find the area of one of the sides and multply it by 6, since theres 6 sides on a cube.

By finding the area of one side, you get 100 square cm (10 times 10)

So then you multply that by 6, and you end up with a total surface area of 600 cm squared.

I hope that made some sense to you,

Grade: E