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Finding the Fourth Proportional to 686.69, 947.64 and 392.12

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Solution

The fourth proportional to 686.69, 947.64 and 392.12 is: 541.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    686.69 : 947.64 = 392.12 : x
  2. Step 2: Convert to fraction form
    686.69/947.64 = 392.12/x
  3. Step 3: Cross multiply
    686.69x = 947.64 × 392.12
  4. Step 4: Simplify right side
    686.69x = 371,588.60
  5. Step 5: Solve for x
    x = 371,588.60/686.69
  6. Step 6: Final answer
    x = 541.13

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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.