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Finding the Fourth Proportional to 686.76, 1,030.74 and 425.94

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Solution

The fourth proportional to 686.76, 1,030.74 and 425.94 is: 639.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    686.76 : 1,030.74 = 425.94 : x
  2. Step 2: Convert to fraction form
    686.76/1,030.74 = 425.94/x
  3. Step 3: Cross multiply
    686.76x = 1,030.74 × 425.94
  4. Step 4: Simplify right side
    686.76x = 439,033.40
  5. Step 5: Solve for x
    x = 439,033.40/686.76
  6. Step 6: Final answer
    x = 639.28

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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.