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Finding the Fourth Proportional to 93.78, 140.40 and 86.76

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Solution

The fourth proportional to 93.78, 140.40 and 86.76 is: 129.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    93.78 : 140.40 = 86.76 : x
  2. Step 2: Convert to fraction form
    93.78/140.40 = 86.76/x
  3. Step 3: Cross multiply
    93.78x = 140.40 × 86.76
  4. Step 4: Simplify right side
    93.78x = 12,181.10
  5. Step 5: Solve for x
    x = 12,181.10/93.78
  6. Step 6: Final answer
    x = 129.89

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.