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Finding the Fourth Proportional to 428.80, 642.24 and 342.40

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Solution

The fourth proportional to 428.80, 642.24 and 342.40 is: 512.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.80 : 642.24 = 342.40 : x
  2. Step 2: Convert to fraction form
    428.80/642.24 = 342.40/x
  3. Step 3: Cross multiply
    428.80x = 642.24 × 342.40
  4. Step 4: Simplify right side
    428.80x = 219,902.98
  5. Step 5: Solve for x
    x = 219,902.98/428.80
  6. Step 6: Final answer
    x = 512.83

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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.