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Finding the Fourth Proportional to 142.80, 197.13 and 87.62

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Solution

The fourth proportional to 142.80, 197.13 and 87.62 is: 120.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    142.80 : 197.13 = 87.62 : x
  2. Step 2: Convert to fraction form
    142.80/197.13 = 87.62/x
  3. Step 3: Cross multiply
    142.80x = 197.13 × 87.62
  4. Step 4: Simplify right side
    142.80x = 17,271.87
  5. Step 5: Solve for x
    x = 17,271.87/142.80
  6. Step 6: Final answer
    x = 120.95

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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.