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Finding the Fourth Proportional to 127.40, 190.68 and 86.72

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Solution

The fourth proportional to 127.40, 190.68 and 86.72 is: 129.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    127.40 : 190.68 = 86.72 : x
  2. Step 2: Convert to fraction form
    127.40/190.68 = 86.72/x
  3. Step 3: Cross multiply
    127.40x = 190.68 × 86.72
  4. Step 4: Simplify right side
    127.40x = 16,535.77
  5. Step 5: Solve for x
    x = 16,535.77/127.40
  6. Step 6: Final answer
    x = 129.79

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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.