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Finding the Fourth Proportional to 426.12, 639.65 and 318.60

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Solution

The fourth proportional to 426.12, 639.65 and 318.60 is: 478.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    426.12 : 639.65 = 318.60 : x
  2. Step 2: Convert to fraction form
    426.12/639.65 = 318.60/x
  3. Step 3: Cross multiply
    426.12x = 639.65 × 318.60
  4. Step 4: Simplify right side
    426.12x = 203,790.90
  5. Step 5: Solve for x
    x = 203,790.90/426.12
  6. Step 6: Final answer
    x = 478.25

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.