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Finding the Fourth Proportional to 686.88, 947.81 and 407.07

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Solution

The fourth proportional to 686.88, 947.81 and 407.07 is: 561.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    686.88 : 947.81 = 407.07 : x
  2. Step 2: Convert to fraction form
    686.88/947.81 = 407.07/x
  3. Step 3: Cross multiply
    686.88x = 947.81 × 407.07
  4. Step 4: Simplify right side
    686.88x = 385,822.98
  5. Step 5: Solve for x
    x = 385,822.98/686.88
  6. Step 6: Final answer
    x = 561.70

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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.