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Finding the Fourth Proportional to 278.54, 417.80 and 86.16

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Solution

The fourth proportional to 278.54, 417.80 and 86.16 is: 129.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    278.54 : 417.80 = 86.16 : x
  2. Step 2: Convert to fraction form
    278.54/417.80 = 86.16/x
  3. Step 3: Cross multiply
    278.54x = 417.80 × 86.16
  4. Step 4: Simplify right side
    278.54x = 35,997.22
  5. Step 5: Solve for x
    x = 35,997.22/278.54
  6. Step 6: Final answer
    x = 129.24

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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.