Question

The surface area of a rectangular prism is 198 cm2. Two of the dimensions are 3 cm and 9 cm. Find the measure of the other dimension.

Answer 1

In this question, it is given that two of the dimensions are 3 cm and 9 cm . Let the other dimension be x cm .

And the surface area of the rectangular prism is given. Now we use the formula of surface area of prism, which is

`A = 2(length* width + width * height + length * height )`

`198 = 2(3*9 + 3*x + 9*x)`

`99 = 27 + 12x`

Subtracting 27 to both sides,

`72 = 12x`

Dividing both sides by 12

`x = 6`

So the length of the remaining dimension is 6 cm .