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Finding the Fourth Proportional to 520.42, 781.31 and 405.60

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Solution

The fourth proportional to 520.42, 781.31 and 405.60 is: 608.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    520.42 : 781.31 = 405.60 : x
  2. Step 2: Convert to fraction form
    520.42/781.31 = 405.60/x
  3. Step 3: Cross multiply
    520.42x = 781.31 × 405.60
  4. Step 4: Simplify right side
    520.42x = 316,893.40
  5. Step 5: Solve for x
    x = 316,893.40/520.42
  6. Step 6: Final answer
    x = 608.92

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.