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Finding the Fourth Proportional to 92.70, 127.80 and 78.78

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Solution

The fourth proportional to 92.70, 127.80 and 78.78 is: 108.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    92.70 : 127.80 = 78.78 : x
  2. Step 2: Convert to fraction form
    92.70/127.80 = 78.78/x
  3. Step 3: Cross multiply
    92.70x = 127.80 × 78.78
  4. Step 4: Simplify right side
    92.70x = 10,068.08
  5. Step 5: Solve for x
    x = 10,068.08/92.70
  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.