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Finding the Fourth Proportional to 709, 978.45 and 398.50

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Solution

The fourth proportional to 709, 978.45 and 398.50 is: 549.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    709 : 978.45 = 398.50 : x
  2. Step 2: Convert to fraction form
    709/978.45 = 398.50/x
  3. Step 3: Cross multiply
    709x = 978.45 × 398.50
  4. Step 4: Simplify right side
    709x = 389,912.33
  5. Step 5: Solve for x
    x = 389,912.33/709
  6. Step 6: Final answer
    x = 549.95

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These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.