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Finding the Fourth Proportional to 428.08, 640.92 and 311.76

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Solution

The fourth proportional to 428.08, 640.92 and 311.76 is: 466.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.08 : 640.92 = 311.76 : x
  2. Step 2: Convert to fraction form
    428.08/640.92 = 311.76/x
  3. Step 3: Cross multiply
    428.08x = 640.92 × 311.76
  4. Step 4: Simplify right side
    428.08x = 199,813.22
  5. Step 5: Solve for x
    x = 199,813.22/428.08
  6. Step 6: Final answer
    x = 466.77

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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.