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Finding the Fourth Proportional to 278.39, 417.57 and 86

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Solution

The fourth proportional to 278.39, 417.57 and 86 is: 129.00

Step by Step Solution

  1. Step 1: Write the proportion equation
    278.39 : 417.57 = 86 : x
  2. Step 2: Convert to fraction form
    278.39/417.57 = 86/x
  3. Step 3: Cross multiply
    278.39x = 417.57 × 86
  4. Step 4: Simplify right side
    278.39x = 35,911.02
  5. Step 5: Solve for x
    x = 35,911.02/278.39
  6. Step 6: Final answer
    x = 129.00

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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.