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Finding the Fourth Proportional to 438.78, 605.15 and 395.58

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Solution

The fourth proportional to 438.78, 605.15 and 395.58 is: 545.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    438.78 : 605.15 = 395.58 : x
  2. Step 2: Convert to fraction form
    438.78/605.15 = 395.58/x
  3. Step 3: Cross multiply
    438.78x = 605.15 × 395.58
  4. Step 4: Simplify right side
    438.78x = 239,389.24
  5. Step 5: Solve for x
    x = 239,389.24/438.78
  6. Step 6: Final answer
    x = 545.57

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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.