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Finding the Fourth Proportional to 712.78, 983.61 and 398.05

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Solution

The fourth proportional to 712.78, 983.61 and 398.05 is: 549.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    712.78 : 983.61 = 398.05 : x
  2. Step 2: Convert to fraction form
    712.78/983.61 = 398.05/x
  3. Step 3: Cross multiply
    712.78x = 983.61 × 398.05
  4. Step 4: Simplify right side
    712.78x = 391,523.50
  5. Step 5: Solve for x
    x = 391,523.50/712.78
  6. Step 6: Final answer
    x = 549.29

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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.