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Finding the Fourth Proportional to 709.48, 978.53 and 485.55

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Solution

The fourth proportional to 709.48, 978.53 and 485.55 is: 669.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    709.48 : 978.53 = 485.55 : x
  2. Step 2: Convert to fraction form
    709.48/978.53 = 485.55/x
  3. Step 3: Cross multiply
    709.48x = 978.53 × 485.55
  4. Step 4: Simplify right side
    709.48x = 475,125.54
  5. Step 5: Solve for x
    x = 475,125.54/709.48
  6. Step 6: Final answer
    x = 669.68

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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.