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Finding the Fourth Proportional to 428.39, 639.15 and 382.22

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Solution

The fourth proportional to 428.39, 639.15 and 382.22 is: 570.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.39 : 639.15 = 382.22 : x
  2. Step 2: Convert to fraction form
    428.39/639.15 = 382.22/x
  3. Step 3: Cross multiply
    428.39x = 639.15 × 382.22
  4. Step 4: Simplify right side
    428.39x = 244,292.72
  5. Step 5: Solve for x
    x = 244,292.72/428.39
  6. Step 6: Final answer
    x = 570.26

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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.