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Finding the Fourth Proportional to 428.16, 639.95 and 372.88

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Solution

The fourth proportional to 428.16, 639.95 and 372.88 is: 557.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.16 : 639.95 = 372.88 : x
  2. Step 2: Convert to fraction form
    428.16/639.95 = 372.88/x
  3. Step 3: Cross multiply
    428.16x = 639.95 × 372.88
  4. Step 4: Simplify right side
    428.16x = 238,624.56
  5. Step 5: Solve for x
    x = 238,624.56/428.16
  6. Step 6: Final answer
    x = 557.33

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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.