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Finding the Fourth Proportional to 42.78, 59.02 and 40.43

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Solution

The fourth proportional to 42.78, 59.02 and 40.43 is: 55.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    42.78 : 59.02 = 40.43 : x
  2. Step 2: Convert to fraction form
    42.78/59.02 = 40.43/x
  3. Step 3: Cross multiply
    42.78x = 59.02 × 40.43
  4. Step 4: Simplify right side
    42.78x = 2,386.18
  5. Step 5: Solve for x
    x = 2,386.18/42.78
  6. Step 6: Final answer
    x = 55.78

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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.