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Finding the Fourth Proportional to 142.88, 197.12 and 91.20

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Solution

The fourth proportional to 142.88, 197.12 and 91.20 is: 125.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    142.88 : 197.12 = 91.20 : x
  2. Step 2: Convert to fraction form
    142.88/197.12 = 91.20/x
  3. Step 3: Cross multiply
    142.88x = 197.12 × 91.20
  4. Step 4: Simplify right side
    142.88x = 17,977.34
  5. Step 5: Solve for x
    x = 17,977.34/142.88
  6. Step 6: Final answer
    x = 125.82

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.