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Finding the Fourth Proportional to 428.58, 639.63 and 379.98

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Solution

The fourth proportional to 428.58, 639.63 and 379.98 is: 567.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.58 : 639.63 = 379.98 : x
  2. Step 2: Convert to fraction form
    428.58/639.63 = 379.98/x
  3. Step 3: Cross multiply
    428.58x = 639.63 × 379.98
  4. Step 4: Simplify right side
    428.58x = 243,046.61
  5. Step 5: Solve for x
    x = 243,046.61/428.58
  6. Step 6: Final answer
    x = 567.10

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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.