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Finding the Fourth Proportional to 426.61, 639.31 and 328.74

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Solution

The fourth proportional to 426.61, 639.31 and 328.74 is: 492.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    426.61 : 639.31 = 328.74 : x
  2. Step 2: Convert to fraction form
    426.61/639.31 = 328.74/x
  3. Step 3: Cross multiply
    426.61x = 639.31 × 328.74
  4. Step 4: Simplify right side
    426.61x = 210,166.77
  5. Step 5: Solve for x
    x = 210,166.77/426.61
  6. Step 6: Final answer
    x = 492.64

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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.