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Finding the Fourth Proportional to 428.84, 638.13 and 427.40

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Solution

The fourth proportional to 428.84, 638.13 and 427.40 is: 635.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.84 : 638.13 = 427.40 : x
  2. Step 2: Convert to fraction form
    428.84/638.13 = 427.40/x
  3. Step 3: Cross multiply
    428.84x = 638.13 × 427.40
  4. Step 4: Simplify right side
    428.84x = 272,736.76
  5. Step 5: Solve for x
    x = 272,736.76/428.84
  6. Step 6: Final answer
    x = 635.99

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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.