## Zara Group Title Two mathematically similar frustums have heights of 20cm and 30cm. The surface area of the smaller frustum is 450cm^2. Calculate the surface area of the larger frustum. one year ago one year ago

1. Zara Group Title

I understand that you have to multiply the smaller frustum's height by 1.5 to get the larger frustum's height, so do you just have to multiply the smaller frustum's area by 1.5 as well?

2. asnaseer Group Title

If the two solids are /similar/ then their surface area will be in a ratio that is the square of the ratio of any of their linear dimensions (e.g. height ratios). Similarly, their volumes will be in a ratio that is the cube of their ratio of linear dimensions

3. Zara Group Title

So you would do 450*1.5^2?

4. asnaseer Group Title

yes, but be careful with what you are squaring, it should be:$450\times(1.5)^2$

5. Zara Group Title

Yup that's what I meant :) Gracias!

6. asnaseer Group Title

yw :)