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Finding the Fourth Proportional to 708.72, 978 and 398.16

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Solution

The fourth proportional to 708.72, 978 and 398.16 is: 549.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    708.72 : 978 = 398.16 : x
  2. Step 2: Convert to fraction form
    708.72/978 = 398.16/x
  3. Step 3: Cross multiply
    708.72x = 978 × 398.16
  4. Step 4: Simplify right side
    708.72x = 389,400.48
  5. Step 5: Solve for x
    x = 389,400.48/708.72
  6. Step 6: Final answer
    x = 549.44

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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.