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Finding the Fourth Proportional to 686.86, 947.72 and 407.18

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Solution

The fourth proportional to 686.86, 947.72 and 407.18 is: 561.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    686.86 : 947.72 = 407.18 : x
  2. Step 2: Convert to fraction form
    686.86/947.72 = 407.18/x
  3. Step 3: Cross multiply
    686.86x = 947.72 × 407.18
  4. Step 4: Simplify right side
    686.86x = 385,889.41
  5. Step 5: Solve for x
    x = 385,889.41/686.86
  6. Step 6: Final answer
    x = 561.82

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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.