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Finding the Fourth Proportional to 129, 178.16 and 128.10

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Solution

The fourth proportional to 129, 178.16 and 128.10 is: 176.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    129 : 178.16 = 128.10 : x
  2. Step 2: Convert to fraction form
    129/178.16 = 128.10/x
  3. Step 3: Cross multiply
    129x = 178.16 × 128.10
  4. Step 4: Simplify right side
    129x = 22,821.66
  5. Step 5: Solve for x
    x = 22,821.66/129
  6. Step 6: Final answer
    x = 176.91

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.