The height of an open box is 1 cm more than the length of a side of its square base. if the open box has a surface area of 96 cm (squared), how do you find the dimensions.?

2 Answers
Sep 11, 2015

The dimensions of the box would be length= width = 4cms and height = 5 cms

Explanation:

Let the side of the square base be x cms, then height would be x+1 cms.

Surface area of the open box, would be area of the base and area of its four faces, =xx +4x*(x+1)

Therefore x^2 +4x^2 +4x=96x2+4x2+4x=96

5x^2 +4x -96=05x2+4x96=0

5x^2 +24x-20x-96=05x2+24x20x96=0

x(5x+24) -4(5x+24)=0x(5x+24)4(5x+24)=0
(x-4)(5x+24)=0(x4)(5x+24)=0. Reject negative value for x, hence x= 4 cms

The dimensions of the box would be length= width = 4cms and height = 5 cms

Sep 11, 2015

You'll find 4cm and 5 cm4cmand5cm

Explanation:

Call the length of the side of the square base xx:
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so:
Surface area AA is the sum of the areas of the 4 sides plus the area of the base, i.e.:
A=4[x*(x+1)]+x^2=96A=4[x(x+1)]+x2=96
4x^2+4x+x^2-96=04x2+4x+x296=0
5x^2+4x-96=05x2+4x96=0
Using the Quadratic Formula:
x_(1,2)=(-4+-sqrt(16+1920))/10=(-4+-44)/10x1,2=4±16+192010=4±4410
The useful solution will then be:
x=40/10=4cmx=4010=4cm