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Finding the Fourth Proportional to 679.29, 1,018.78 and 313.88

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Solution

The fourth proportional to 679.29, 1,018.78 and 313.88 is: 470.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    679.29 : 1,018.78 = 313.88 : x
  2. Step 2: Convert to fraction form
    679.29/1,018.78 = 313.88/x
  3. Step 3: Cross multiply
    679.29x = 1,018.78 × 313.88
  4. Step 4: Simplify right side
    679.29x = 319,768.79
  5. Step 5: Solve for x
    x = 319,768.79/679.29
  6. Step 6: Final answer
    x = 470.74

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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.