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Finding the Fourth Proportional to 78.78, 118.14 and 65.22

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Solution

The fourth proportional to 78.78, 118.14 and 65.22 is: 97.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.78 : 118.14 = 65.22 : x
  2. Step 2: Convert to fraction form
    78.78/118.14 = 65.22/x
  3. Step 3: Cross multiply
    78.78x = 118.14 × 65.22
  4. Step 4: Simplify right side
    78.78x = 7,705.09
  5. Step 5: Solve for x
    x = 7,705.09/78.78
  6. Step 6: Final answer
    x = 97.81

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.