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Finding the Fourth Proportional to 54.78, 75.65 and 39.28

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Solution

The fourth proportional to 54.78, 75.65 and 39.28 is: 54.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    54.78 : 75.65 = 39.28 : x
  2. Step 2: Convert to fraction form
    54.78/75.65 = 39.28/x
  3. Step 3: Cross multiply
    54.78x = 75.65 × 39.28
  4. Step 4: Simplify right side
    54.78x = 2,971.53
  5. Step 5: Solve for x
    x = 2,971.53/54.78
  6. Step 6: Final answer
    x = 54.24

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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.