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Finding the Fourth Proportional to 686.60, 947.90 and 438.12

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Solution

The fourth proportional to 686.60, 947.90 and 438.12 is: 604.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    686.60 : 947.90 = 438.12 : x
  2. Step 2: Convert to fraction form
    686.60/947.90 = 438.12/x
  3. Step 3: Cross multiply
    686.60x = 947.90 × 438.12
  4. Step 4: Simplify right side
    686.60x = 415,291.76
  5. Step 5: Solve for x
    x = 415,291.76/686.60
  6. Step 6: Final answer
    x = 604.86

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.