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Finding the Fourth Proportional to 428.70, 641.88 and 312.54

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Solution

The fourth proportional to 428.70, 641.88 and 312.54 is: 467.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.70 : 641.88 = 312.54 : x
  2. Step 2: Convert to fraction form
    428.70/641.88 = 312.54/x
  3. Step 3: Cross multiply
    428.70x = 641.88 × 312.54
  4. Step 4: Simplify right side
    428.70x = 200,613.18
  5. Step 5: Solve for x
    x = 200,613.18/428.70
  6. Step 6: Final answer
    x = 467.96

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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.