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Finding the Fourth Proportional to 686.76, 1,030.70 and 378.82

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Solution

The fourth proportional to 686.76, 1,030.70 and 378.82 is: 568.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    686.76 : 1,030.70 = 378.82 : x
  2. Step 2: Convert to fraction form
    686.76/1,030.70 = 378.82/x
  3. Step 3: Cross multiply
    686.76x = 1,030.70 × 378.82
  4. Step 4: Simplify right side
    686.76x = 390,449.77
  5. Step 5: Solve for x
    x = 390,449.77/686.76
  6. Step 6: Final answer
    x = 568.54

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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.