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Finding the Fourth Proportional to 72.78, 109.14 and 65.64

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Solution

The fourth proportional to 72.78, 109.14 and 65.64 is: 98.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.78 : 109.14 = 65.64 : x
  2. Step 2: Convert to fraction form
    72.78/109.14 = 65.64/x
  3. Step 3: Cross multiply
    72.78x = 109.14 × 65.64
  4. Step 4: Simplify right side
    72.78x = 7,163.95
  5. Step 5: Solve for x
    x = 7,163.95/72.78
  6. Step 6: Final answer
    x = 98.43

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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.