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Finding the Fourth Proportional to 54.90, 75.78 and 39.38

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Solution

The fourth proportional to 54.90, 75.78 and 39.38 is: 54.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    54.90 : 75.78 = 39.38 : x
  2. Step 2: Convert to fraction form
    54.90/75.78 = 39.38/x
  3. Step 3: Cross multiply
    54.90x = 75.78 × 39.38
  4. Step 4: Simplify right side
    54.90x = 2,983.84
  5. Step 5: Solve for x
    x = 2,983.84/54.90
  6. Step 6: Final answer
    x = 54.35

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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.