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Finding the Fourth Proportional to 709.55, 978.78 and 425.90

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Solution

The fourth proportional to 709.55, 978.78 and 425.90 is: 587.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    709.55 : 978.78 = 425.90 : x
  2. Step 2: Convert to fraction form
    709.55/978.78 = 425.90/x
  3. Step 3: Cross multiply
    709.55x = 978.78 × 425.90
  4. Step 4: Simplify right side
    709.55x = 416,862.78
  5. Step 5: Solve for x
    x = 416,862.78/709.55
  6. Step 6: Final answer
    x = 587.50

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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.