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Finding the Fourth Proportional to 428.39, 641.72 and 312.26

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Solution

The fourth proportional to 428.39, 641.72 and 312.26 is: 467.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.39 : 641.72 = 312.26 : x
  2. Step 2: Convert to fraction form
    428.39/641.72 = 312.26/x
  3. Step 3: Cross multiply
    428.39x = 641.72 × 312.26
  4. Step 4: Simplify right side
    428.39x = 200,381.06
  5. Step 5: Solve for x
    x = 200,381.06/428.39
  6. Step 6: Final answer
    x = 467.76

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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.