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Finding the Fourth Proportional to 429.40, 644.18 and 140.76

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Solution

The fourth proportional to 429.40, 644.18 and 140.76 is: 211.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    429.40 : 644.18 = 140.76 : x
  2. Step 2: Convert to fraction form
    429.40/644.18 = 140.76/x
  3. Step 3: Cross multiply
    429.40x = 644.18 × 140.76
  4. Step 4: Simplify right side
    429.40x = 90,674.78
  5. Step 5: Solve for x
    x = 90,674.78/429.40
  6. Step 6: Final answer
    x = 211.17

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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.