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Finding the Fourth Proportional to 678.34, 1,017.82 and 418.74

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Solution

The fourth proportional to 678.34, 1,017.82 and 418.74 is: 628.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.34 : 1,017.82 = 418.74 : x
  2. Step 2: Convert to fraction form
    678.34/1,017.82 = 418.74/x
  3. Step 3: Cross multiply
    678.34x = 1,017.82 × 418.74
  4. Step 4: Simplify right side
    678.34x = 426,201.95
  5. Step 5: Solve for x
    x = 426,201.95/678.34
  6. Step 6: Final answer
    x = 628.30

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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.