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Finding the Fourth Proportional to 127.38, 175.70 and 78.20

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Solution

The fourth proportional to 127.38, 175.70 and 78.20 is: 107.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    127.38 : 175.70 = 78.20 : x
  2. Step 2: Convert to fraction form
    127.38/175.70 = 78.20/x
  3. Step 3: Cross multiply
    127.38x = 175.70 × 78.20
  4. Step 4: Simplify right side
    127.38x = 13,739.74
  5. Step 5: Solve for x
    x = 13,739.74/127.38
  6. Step 6: Final answer
    x = 107.86

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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.