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Finding the Fourth Proportional to 678.96, 1,018.08 and 313.43

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Solution

The fourth proportional to 678.96, 1,018.08 and 313.43 is: 469.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.96 : 1,018.08 = 313.43 : x
  2. Step 2: Convert to fraction form
    678.96/1,018.08 = 313.43/x
  3. Step 3: Cross multiply
    678.96x = 1,018.08 × 313.43
  4. Step 4: Simplify right side
    678.96x = 319,099.36
  5. Step 5: Solve for x
    x = 319,099.36/678.96
  6. Step 6: Final answer
    x = 469.98

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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.