Math Problem Statement

The diagram shows two mathematically similar solids A and B. The volume of solid A is 1125 cm³, and the volume of solid B is 576 cm³. Given that the surface area of solid A + surface area of solid B = 3198 cm², calculate the surface area of solid B.

Solution

To solve this problem, we need to use the concept of similar solids and the ratios of their volumes and surface areas.

Given:

  1. Volumes of solids:

    • Volume of solid AA (VAV_A) = 1125 cm³
    • Volume of solid BB (VBV_B) = 576 cm³
  2. Surface area information:

    • Total surface area of solid AA and solid BB is 3198 cm².

We need to find the surface area of solid BB.

Step 1: Find the Ratio of the Volumes

Since solids AA and BB are similar, the ratio of their volumes is given by: (Volume of BVolume of A)=(Scale factor of BScale factor of A)3\left(\frac{\text{Volume of } B}{\text{Volume of } A}\right) = \left(\frac{\text{Scale factor of } B}{\text{Scale factor of } A}\right)^3

Let kk be the scale factor of BB compared to AA. Then: k3=VBVA=5761125k^3 = \frac{V_B}{V_A} = \frac{576}{1125}

Calculating this ratio: k3=5761125=0.512k^3 = \frac{576}{1125} = 0.512

Now, take the cube root to find kk: k=0.51230.8k = \sqrt[3]{0.512} \approx 0.8

Step 2: Use the Scale Factor to Find the Surface Area Ratio

For similar solids, the ratio of their surface areas is the square of the scale factor: Surface Area of BSurface Area of A=k2=(0.8)2=0.64\frac{\text{Surface Area of } B}{\text{Surface Area of } A} = k^2 = (0.8)^2 = 0.64

Let the surface area of solid AA be SAS_A and that of solid BB be SBS_B.

We know: SA+SB=3198S_A + S_B = 3198

And from the surface area ratio: SB=0.64SAS_B = 0.64 S_A

Step 3: Solve for SAS_A and SBS_B

Substitute SB=0.64SAS_B = 0.64 S_A into the total surface area equation: SA+0.64SA=3198S_A + 0.64 S_A = 3198 1.64SA=31981.64 S_A = 3198 SA=31981.641950cm2S_A = \frac{3198}{1.64} \approx 1950 \, \text{cm}^2

Now, substitute SAS_A back to find SBS_B: SB=0.64×19501248cm2S_B = 0.64 \times 1950 \approx 1248 \, \text{cm}^2

Answer

The surface area of solid BB is approximately: 1248cm2\boxed{1248 \, \text{cm}^2}

Would you like more details on any step, or have further questions?


Here are 5 related questions to explore this topic further:

  1. How would the answer change if the solids were not similar?
  2. What if only the ratio of the volumes was given, without the actual volume values?
  3. How can this problem be extended to find other properties, like height, if they are similar shapes?
  4. Why do we use the square of the scale factor for surface area and the cube for volume?
  5. How would this approach differ if we were working with 2D similar figures rather than 3D solids?

Tip: When working with similar figures, remember that length, area, and volume scale differently: linearly, by the square, and by the cube, respectively.

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Math Problem Analysis

Mathematical Concepts

Geometry
Similar Solids
Volume and Surface Area Ratios

Formulas

Volume ratio of similar solids: (Volume of B / Volume of A) = (Scale factor)^3
Surface area ratio of similar solids: (Surface Area of B / Surface Area of A) = (Scale factor)^2

Theorems

Ratios of Volumes and Surface Areas of Similar Solids

Suitable Grade Level

Grades 9-11