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Finding the Fourth Proportional to 127.79, 176.40 and 78.68

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Solution

The fourth proportional to 127.79, 176.40 and 78.68 is: 108.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    127.79 : 176.40 = 78.68 : x
  2. Step 2: Convert to fraction form
    127.79/176.40 = 78.68/x
  3. Step 3: Cross multiply
    127.79x = 176.40 × 78.68
  4. Step 4: Simplify right side
    127.79x = 13,879.15
  5. Step 5: Solve for x
    x = 13,879.15/127.79
  6. Step 6: Final answer
    x = 108.61

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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.