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Finding the Fourth Proportional to 428.52, 638.70 and 395.64

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Solution

The fourth proportional to 428.52, 638.70 and 395.64 is: 589.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.52 : 638.70 = 395.64 : x
  2. Step 2: Convert to fraction form
    428.52/638.70 = 395.64/x
  3. Step 3: Cross multiply
    428.52x = 638.70 × 395.64
  4. Step 4: Simplify right side
    428.52x = 252,695.27
  5. Step 5: Solve for x
    x = 252,695.27/428.52
  6. Step 6: Final answer
    x = 589.69

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.