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Finding the Fourth Proportional to 142.79, 212.30 and 139.14

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Solution

The fourth proportional to 142.79, 212.30 and 139.14 is: 206.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    142.79 : 212.30 = 139.14 : x
  2. Step 2: Convert to fraction form
    142.79/212.30 = 139.14/x
  3. Step 3: Cross multiply
    142.79x = 212.30 × 139.14
  4. Step 4: Simplify right side
    142.79x = 29,538.73
  5. Step 5: Solve for x
    x = 29,538.73/142.79
  6. Step 6: Final answer
    x = 206.88

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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.