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Finding the Fourth Proportional to 712.87, 983.78 and 398.15

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Solution

The fourth proportional to 712.87, 983.78 and 398.15 is: 549.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    712.87 : 983.78 = 398.15 : x
  2. Step 2: Convert to fraction form
    712.87/983.78 = 398.15/x
  3. Step 3: Cross multiply
    712.87x = 983.78 × 398.15
  4. Step 4: Simplify right side
    712.87x = 391,690.28
  5. Step 5: Solve for x
    x = 391,690.28/712.87
  6. Step 6: Final answer
    x = 549.46

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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.