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Finding the Fourth Proportional to 405.47, 605.28 and 387.74

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Solution

The fourth proportional to 405.47, 605.28 and 387.74 is: 578.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    405.47 : 605.28 = 387.74 : x
  2. Step 2: Convert to fraction form
    405.47/605.28 = 387.74/x
  3. Step 3: Cross multiply
    405.47x = 605.28 × 387.74
  4. Step 4: Simplify right side
    405.47x = 234,688.24
  5. Step 5: Solve for x
    x = 234,688.24/405.47
  6. Step 6: Final answer
    x = 578.81

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.