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Finding the Fourth Proportional to 142.15, 213.30 and 77.15

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Solution

The fourth proportional to 142.15, 213.30 and 77.15 is: 115.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    142.15 : 213.30 = 77.15 : x
  2. Step 2: Convert to fraction form
    142.15/213.30 = 77.15/x
  3. Step 3: Cross multiply
    142.15x = 213.30 × 77.15
  4. Step 4: Simplify right side
    142.15x = 16,455.03
  5. Step 5: Solve for x
    x = 16,455.03/142.15
  6. Step 6: Final answer
    x = 115.76

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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.