Similar solids share one linear scale factor for their matching lengths. A surface-area ratio gives the square of that factor, but volume needs its cube. Choose the direction from the known solid to the unknown one, use Desmos to find the length factor, then apply it to the known volume. Using the area ratio directly on volume skips a dimension.
Hints
- Hint 1
For similar solids, every matching length changes by one factor, . An area changes by . Which way should you write the area ratio to find the factor from cone A to cone B?
- Hint 2
A length factor must be positive. Once you have an equation for its square, find the positive value that makes the equation true.
- Hint 3
Volume depends on three length directions, so it changes by . Multiply cone A's volume by the cube of the A-to-B factor, not by the area ratio.
Step-by-step
Find the length factor, then scale the volume
Step 1Turn the area ratio into a scale-factor equation
Let be the linear scale factor from A to B: each length in B is times its match in A. Lateral surface area is the curved outside of a cone; like any area, it changes by . Put B's area over A's to match the direction from A to B:
- Step 2
Find the positive length factor
Type in Desmos. The asks Desmos to find , and the restriction keeps it positive because lengths can't be negative. Under PARAMETERS, Desmos shows , or .
- Step 3
Set up the volume change
Cone A's volume is . A volume uses the cube of the same length factor that an area squares. So cube to get cone B's volume: . Using instead would apply an area factor to a volume.
- Step 4
Calculate cone B's volume
Type beneath the regression. Desmos shows ; that's the number multiplying . Cone B's volume is cubic centimeters. Choice D.