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Finding the Fourth Proportional to 78.62, 117.02 and 77.86

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Solution

The fourth proportional to 78.62, 117.02 and 77.86 is: 115.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.62 : 117.02 = 77.86 : x
  2. Step 2: Convert to fraction form
    78.62/117.02 = 77.86/x
  3. Step 3: Cross multiply
    78.62x = 117.02 × 77.86
  4. Step 4: Simplify right side
    78.62x = 9,111.28
  5. Step 5: Solve for x
    x = 9,111.28/78.62
  6. Step 6: Final answer
    x = 115.89

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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.