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Finding the Fourth Proportional to 428.21, 640.92 and 242.61

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Solution

The fourth proportional to 428.21, 640.92 and 242.61 is: 363.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.21 : 640.92 = 242.61 : x
  2. Step 2: Convert to fraction form
    428.21/640.92 = 242.61/x
  3. Step 3: Cross multiply
    428.21x = 640.92 × 242.61
  4. Step 4: Simplify right side
    428.21x = 155,493.60
  5. Step 5: Solve for x
    x = 155,493.60/428.21
  6. Step 6: Final answer
    x = 363.12

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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.