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Finding the Fourth Proportional to 142.54, 213.68 and 91.20

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Solution

The fourth proportional to 142.54, 213.68 and 91.20 is: 136.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    142.54 : 213.68 = 91.20 : x
  2. Step 2: Convert to fraction form
    142.54/213.68 = 91.20/x
  3. Step 3: Cross multiply
    142.54x = 213.68 × 91.20
  4. Step 4: Simplify right side
    142.54x = 19,487.04
  5. Step 5: Solve for x
    x = 19,487.04/142.54
  6. Step 6: Final answer
    x = 136.71

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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.