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Finding the Fourth Proportional to 686.40, 1,030.08 and 394.38

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Solution

The fourth proportional to 686.40, 1,030.08 and 394.38 is: 591.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    686.40 : 1,030.08 = 394.38 : x
  2. Step 2: Convert to fraction form
    686.40/1,030.08 = 394.38/x
  3. Step 3: Cross multiply
    686.40x = 1,030.08 × 394.38
  4. Step 4: Simplify right side
    686.40x = 406,242.95
  5. Step 5: Solve for x
    x = 406,242.95/686.40
  6. Step 6: Final answer
    x = 591.85

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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.