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Finding the Fourth Proportional to 709, 978.47 and 398.50

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Solution

The fourth proportional to 709, 978.47 and 398.50 is: 549.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    709 : 978.47 = 398.50 : x
  2. Step 2: Convert to fraction form
    709/978.47 = 398.50/x
  3. Step 3: Cross multiply
    709x = 978.47 × 398.50
  4. Step 4: Simplify right side
    709x = 389,920.30
  5. Step 5: Solve for x
    x = 389,920.30/709
  6. Step 6: Final answer
    x = 549.96

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