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Finding the Fourth Proportional to 686.39, 947.18 and 406.64

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Solution

The fourth proportional to 686.39, 947.18 and 406.64 is: 561.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    686.39 : 947.18 = 406.64 : x
  2. Step 2: Convert to fraction form
    686.39/947.18 = 406.64/x
  3. Step 3: Cross multiply
    686.39x = 947.18 × 406.64
  4. Step 4: Simplify right side
    686.39x = 385,164.66
  5. Step 5: Solve for x
    x = 385,164.66/686.39
  6. Step 6: Final answer
    x = 561.15

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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.