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Finding the Fourth Proportional to 712.80, 983.61 and 398.12

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Solution

The fourth proportional to 712.80, 983.61 and 398.12 is: 549.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    712.80 : 983.61 = 398.12 : x
  2. Step 2: Convert to fraction form
    712.80/983.61 = 398.12/x
  3. Step 3: Cross multiply
    712.80x = 983.61 × 398.12
  4. Step 4: Simplify right side
    712.80x = 391,589.90
  5. Step 5: Solve for x
    x = 391,589.90/712.80
  6. Step 6: Final answer
    x = 549.37

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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.