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Finding the Fourth Proportional to 678.21, 1,018.44 and 423.33

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Solution

The fourth proportional to 678.21, 1,018.44 and 423.33 is: 635.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.21 : 1,018.44 = 423.33 : x
  2. Step 2: Convert to fraction form
    678.21/1,018.44 = 423.33/x
  3. Step 3: Cross multiply
    678.21x = 1,018.44 × 423.33
  4. Step 4: Simplify right side
    678.21x = 431,136.21
  5. Step 5: Solve for x
    x = 431,136.21/678.21
  6. Step 6: Final answer
    x = 635.70

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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.