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Finding the Fourth Proportional to 521.73, 781.79 and 405.90

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Solution

The fourth proportional to 521.73, 781.79 and 405.90 is: 608.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    521.73 : 781.79 = 405.90 : x
  2. Step 2: Convert to fraction form
    521.73/781.79 = 405.90/x
  3. Step 3: Cross multiply
    521.73x = 781.79 × 405.90
  4. Step 4: Simplify right side
    521.73x = 317,326.53
  5. Step 5: Solve for x
    x = 317,326.53/521.73
  6. Step 6: Final answer
    x = 608.22

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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.