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Finding the Fourth Proportional to 678.56, 1,020.90 and 404.84

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Solution

The fourth proportional to 678.56, 1,020.90 and 404.84 is: 609.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.56 : 1,020.90 = 404.84 : x
  2. Step 2: Convert to fraction form
    678.56/1,020.90 = 404.84/x
  3. Step 3: Cross multiply
    678.56x = 1,020.90 × 404.84
  4. Step 4: Simplify right side
    678.56x = 413,305.23
  5. Step 5: Solve for x
    x = 413,305.23/678.56
  6. Step 6: Final answer
    x = 609.10

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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.