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Finding the Fourth Proportional to 142.18, 213.09 and 77.18

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Solution

The fourth proportional to 142.18, 213.09 and 77.18 is: 115.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    142.18 : 213.09 = 77.18 : x
  2. Step 2: Convert to fraction form
    142.18/213.09 = 77.18/x
  3. Step 3: Cross multiply
    142.18x = 213.09 × 77.18
  4. Step 4: Simplify right side
    142.18x = 16,444.83
  5. Step 5: Solve for x
    x = 16,444.83/142.18
  6. Step 6: Final answer
    x = 115.67

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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.