Alberta Free Tutoring And Homework Help For Math 20-2

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how do i find the linear scale factor, when  given 4 cm x 3 cm x 2 cm, and 24 x 18 x 12, they ask for the surface area and volume for the original and i can't use the first measurements by themself?

2 years ago

Answered By John Luke W

The "linear scale factor" is just the factor that each line is scaled up by. Find the corresponding sides (for example, the two largest sides on each shape) and divide them:

24/4 = 6

There's our linear scale factor -- each side is scaled up by a factor of 6. We can check:

4*6 = 243*6 = 182*6 = 12

So our big and small shapes are the same. So far so good.

It sounds like they're asking you to use the "big" dimensions to find the surface area and volume for the "small" shape, right? Well for square measurements, we can downsize by dividing by 6 twice, and for cubic measurements, we can divide by 6 three times. So:

1. Find surface area of the big shape2. Divide by 36  (divide by 6, divide by 6)

1. Find volume of the big shape2. Divide by 216 (divide by 6, divide by 6, divide by 6)

Make sense?