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Finding the Fourth Proportional to 686.45, 947.31 and 406.83

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Solution

The fourth proportional to 686.45, 947.31 and 406.83 is: 561.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    686.45 : 947.31 = 406.83 : x
  2. Step 2: Convert to fraction form
    686.45/947.31 = 406.83/x
  3. Step 3: Cross multiply
    686.45x = 947.31 × 406.83
  4. Step 4: Simplify right side
    686.45x = 385,390.07
  5. Step 5: Solve for x
    x = 385,390.07/686.45
  6. Step 6: Final answer
    x = 561.42

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1.5x scale

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.