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Finding the Fourth Proportional to 686.82, 1,030.22 and 321.40

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Solution

The fourth proportional to 686.82, 1,030.22 and 321.40 is: 482.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    686.82 : 1,030.22 = 321.40 : x
  2. Step 2: Convert to fraction form
    686.82/1,030.22 = 321.40/x
  3. Step 3: Cross multiply
    686.82x = 1,030.22 × 321.40
  4. Step 4: Simplify right side
    686.82x = 331,112.71
  5. Step 5: Solve for x
    x = 331,112.71/686.82
  6. Step 6: Final answer
    x = 482.10

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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.