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Finding the Fourth Proportional to 127.20, 175.60 and 85.72

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Solution

The fourth proportional to 127.20, 175.60 and 85.72 is: 118.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    127.20 : 175.60 = 85.72 : x
  2. Step 2: Convert to fraction form
    127.20/175.60 = 85.72/x
  3. Step 3: Cross multiply
    127.20x = 175.60 × 85.72
  4. Step 4: Simplify right side
    127.20x = 15,052.43
  5. Step 5: Solve for x
    x = 15,052.43/127.20
  6. Step 6: Final answer
    x = 118.34

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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.