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Finding the Fourth Proportional to 678.67, 1,019.36 and 405.29

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Solution

The fourth proportional to 678.67, 1,019.36 and 405.29 is: 608.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.67 : 1,019.36 = 405.29 : x
  2. Step 2: Convert to fraction form
    678.67/1,019.36 = 405.29/x
  3. Step 3: Cross multiply
    678.67x = 1,019.36 × 405.29
  4. Step 4: Simplify right side
    678.67x = 413,136.41
  5. Step 5: Solve for x
    x = 413,136.41/678.67
  6. Step 6: Final answer
    x = 608.75

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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.