Posted by **nicole** on Friday, September 13, 2013 at 7:43pm.

by cutting a square out of each corner of a sheet of card (30cm by 21cm)and folding up the sides,i ca make an open box with a capacity of 1080cm^3.What is the area in cm^2 of each of the squares i have to cut out?

- math -
**Steve**, Friday, September 13, 2013 at 7:46pm
this problem has been solved in many of the related questions below, with different numbers. Follow some of them and give it a shot. What do you get?

- math -
**Graham**, Friday, September 13, 2013 at 8:16pm
Let the sides you cut out be x centimetres long.

The volume is then:

(30-2x)(21-2x)x = 1080

Expanding:

4 x^3 - 102 x^2 + 630 x - 1080 = 0

Look for common factors:

(x-3)(4x^2 - 90x + 360) = 0

Found one root, solve the quadratic for the other.

## Answer this Question

## Related Questions

- math - a square sheet of tin 30cm on a side is to be used to make an open - top ...
- algebra - Open-top box. Thomas is going to make an open-top box by cutting equal...
- Calc - You want to make a rectangular box, open at the top, by cutting the same ...
- algebra - open box made from 33 x 33 inch sheet of metal by cutting out x-inch ...
- Algebra - An open box is to be constructed from a rectangular sheet of tin 3 ...
- Pre Calc - an open box is to be formed by cutting squares from a square sheet of...
- Maths - A box with no top is to be built by taking a 6'' - by - 10'' sheet of ...
- Geometry - Imagine a piece of square paper that measures 20 by 20 cm. You can ...
- math - you want to make an open-topped box from a 20 cm by 20 cm piece of ...
- Math - A box with an open top is to be constructed from a rectangular piece of ...