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Finding the Fourth Proportional to 428.67, 643.17 and 140.10

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Solution

The fourth proportional to 428.67, 643.17 and 140.10 is: 210.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.67 : 643.17 = 140.10 : x
  2. Step 2: Convert to fraction form
    428.67/643.17 = 140.10/x
  3. Step 3: Cross multiply
    428.67x = 643.17 × 140.10
  4. Step 4: Simplify right side
    428.67x = 90,108.12
  5. Step 5: Solve for x
    x = 90,108.12/428.67
  6. Step 6: Final answer
    x = 210.20

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.