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Finding the Fourth Proportional to 708.54, 978.72 and 487.11

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Solution

The fourth proportional to 708.54, 978.72 and 487.11 is: 672.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    708.54 : 978.72 = 487.11 : x
  2. Step 2: Convert to fraction form
    708.54/978.72 = 487.11/x
  3. Step 3: Cross multiply
    708.54x = 978.72 × 487.11
  4. Step 4: Simplify right side
    708.54x = 476,741.86
  5. Step 5: Solve for x
    x = 476,741.86/708.54
  6. Step 6: Final answer
    x = 672.85

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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.