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Finding the Fourth Proportional to 678.21, 1,011.81 and 628.59

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Solution

The fourth proportional to 678.21, 1,011.81 and 628.59 is: 937.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.21 : 1,011.81 = 628.59 : x
  2. Step 2: Convert to fraction form
    678.21/1,011.81 = 628.59/x
  3. Step 3: Cross multiply
    678.21x = 1,011.81 × 628.59
  4. Step 4: Simplify right side
    678.21x = 636,013.65
  5. Step 5: Solve for x
    x = 636,013.65/678.21
  6. Step 6: Final answer
    x = 937.78

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.