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Finding the Fourth Proportional to 142.40, 212.08 and 140.72

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Solution

The fourth proportional to 142.40, 212.08 and 140.72 is: 209.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    142.40 : 212.08 = 140.72 : x
  2. Step 2: Convert to fraction form
    142.40/212.08 = 140.72/x
  3. Step 3: Cross multiply
    142.40x = 212.08 × 140.72
  4. Step 4: Simplify right side
    142.40x = 29,843.90
  5. Step 5: Solve for x
    x = 29,843.90/142.40
  6. Step 6: Final answer
    x = 209.58

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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.