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Finding the Fourth Proportional to 55.78, 76.88 and 39.38

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Solution

The fourth proportional to 55.78, 76.88 and 39.38 is: 54.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    55.78 : 76.88 = 39.38 : x
  2. Step 2: Convert to fraction form
    55.78/76.88 = 39.38/x
  3. Step 3: Cross multiply
    55.78x = 76.88 × 39.38
  4. Step 4: Simplify right side
    55.78x = 3,027.34
  5. Step 5: Solve for x
    x = 3,027.34/55.78
  6. Step 6: Final answer
    x = 54.27

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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.