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Finding the Fourth Proportional to 86.29, 129.24 and 55.78

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Solution

The fourth proportional to 86.29, 129.24 and 55.78 is: 83.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.29 : 129.24 = 55.78 : x
  2. Step 2: Convert to fraction form
    86.29/129.24 = 55.78/x
  3. Step 3: Cross multiply
    86.29x = 129.24 × 55.78
  4. Step 4: Simplify right side
    86.29x = 7,209.01
  5. Step 5: Solve for x
    x = 7,209.01/86.29
  6. Step 6: Final answer
    x = 83.54

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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.