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Finding the Fourth Proportional to 712.69, 983.40 and 397.90

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Solution

The fourth proportional to 712.69, 983.40 and 397.90 is: 549.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    712.69 : 983.40 = 397.90 : x
  2. Step 2: Convert to fraction form
    712.69/983.40 = 397.90/x
  3. Step 3: Cross multiply
    712.69x = 983.40 × 397.90
  4. Step 4: Simplify right side
    712.69x = 391,294.86
  5. Step 5: Solve for x
    x = 391,294.86/712.69
  6. Step 6: Final answer
    x = 549.04

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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.