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Finding the Fourth Proportional to 78.38, 116.82 and 77.61

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Solution

The fourth proportional to 78.38, 116.82 and 77.61 is: 115.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.38 : 116.82 = 77.61 : x
  2. Step 2: Convert to fraction form
    78.38/116.82 = 77.61/x
  3. Step 3: Cross multiply
    78.38x = 116.82 × 77.61
  4. Step 4: Simplify right side
    78.38x = 9,066.40
  5. Step 5: Solve for x
    x = 9,066.40/78.38
  6. Step 6: Final answer
    x = 115.68

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.