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Finding the Fourth Proportional to 708.20, 978.18 and 685.52

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Solution

The fourth proportional to 708.20, 978.18 and 685.52 is: 946.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    708.20 : 978.18 = 685.52 : x
  2. Step 2: Convert to fraction form
    708.20/978.18 = 685.52/x
  3. Step 3: Cross multiply
    708.20x = 978.18 × 685.52
  4. Step 4: Simplify right side
    708.20x = 670,561.95
  5. Step 5: Solve for x
    x = 670,561.95/708.20
  6. Step 6: Final answer
    x = 946.85

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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.