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Finding the Fourth Proportional to 678.69, 1,018.17 and 313.25

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Solution

The fourth proportional to 678.69, 1,018.17 and 313.25 is: 469.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.69 : 1,018.17 = 313.25 : x
  2. Step 2: Convert to fraction form
    678.69/1,018.17 = 313.25/x
  3. Step 3: Cross multiply
    678.69x = 1,018.17 × 313.25
  4. Step 4: Simplify right side
    678.69x = 318,936.66
  5. Step 5: Solve for x
    x = 318,936.66/678.69
  6. Step 6: Final answer
    x = 469.93

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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.