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Finding the Fourth Proportional to 678.20, 1,017.30 and 607.80

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Solution

The fourth proportional to 678.20, 1,017.30 and 607.80 is: 911.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.20 : 1,017.30 = 607.80 : x
  2. Step 2: Convert to fraction form
    678.20/1,017.30 = 607.80/x
  3. Step 3: Cross multiply
    678.20x = 1,017.30 × 607.80
  4. Step 4: Simplify right side
    678.20x = 618,314.94
  5. Step 5: Solve for x
    x = 618,314.94/678.20
  6. Step 6: Final answer
    x = 911.70

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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.