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Finding the Fourth Proportional to 686.94, 1,030.78 and 321.64

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Solution

The fourth proportional to 686.94, 1,030.78 and 321.64 is: 482.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    686.94 : 1,030.78 = 321.64 : x
  2. Step 2: Convert to fraction form
    686.94/1,030.78 = 321.64/x
  3. Step 3: Cross multiply
    686.94x = 1,030.78 × 321.64
  4. Step 4: Simplify right side
    686.94x = 331,540.08
  5. Step 5: Solve for x
    x = 331,540.08/686.94
  6. Step 6: Final answer
    x = 482.63

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.