Question

A cube of side length 10 cm is intersected by a plane perpendicular to the base as shown.

Answer 1

Part 1: Describe the shape of the cross section formed by the cube and the intersecting plane.
Part 2: Find the perimeter of the cross section. Show your work.

Answer 2

triangle

Answer 3

Since you know it's a cube, you know all of the sides are 10cm long. So one leg of the triangle must be 10-7cm long and the other 10-6 cm long.

Answer 4

You can just look at part one and see that the volume is a "triangular prism"

Answer 5

The second part involves finding the lengths of the legs and obtaining a perimeter, which as I've described is the second part.

Answer 6

3cm long ? and 4 cm long?

Answer 7

That's correct. You can either use pythagorean theorem or you know of the "special triangle" to obtain the length of the other side.

Answer 8

i have no idea what your trying to say

Answer 9

You now know two lengths of the triangle. You must find the other one. You can use the pythagorean theorem. However, there is a special right triangle with just those lengths. The perimeter of a triangle is simply the lengths of the sides added up.

Answer 10

whats the pythagorean theorem

Answer 11

a2 + b2 = c2

Answer 12

256?

Answer 13

That is the pythagorean theorem. "C" is the hypotenuse, which is what you need.

Answer 14

256?

Answer 15

That is incorrect.

Answer 16

Remember that one side (A) = 3. The other side (B) = 4. Now find C.

Answer 17

3^2=9

Answer 18

4^2=16

Answer 19

9+16=25

Answer 20

25^2=625

Answer 21

No no, take the square ROOT of 25. Not the SQUARE of 25.

Answer 22

5

Answer 23

You got it. That's a 3:4:5 right triangle. You can remember that one, might make life easier one day. Add those up and thats your triangular perimeter.

Answer 24

No, your sides are 3, 4, and 5. Add those up. That is your perimeter.

Answer 25

12

Answer 26

That is correct.

Answer 27

kthanks