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Finding the Fourth Proportional to 142.28, 212.44 and 139.76

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Solution

The fourth proportional to 142.28, 212.44 and 139.76 is: 208.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    142.28 : 212.44 = 139.76 : x
  2. Step 2: Convert to fraction form
    142.28/212.44 = 139.76/x
  3. Step 3: Cross multiply
    142.28x = 212.44 × 139.76
  4. Step 4: Simplify right side
    142.28x = 29,690.61
  5. Step 5: Solve for x
    x = 29,690.61/142.28
  6. Step 6: Final answer
    x = 208.68

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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.