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Finding the Fourth Proportional to 78.47, 108.49 and 69.20

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Solution

The fourth proportional to 78.47, 108.49 and 69.20 is: 95.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.47 : 108.49 = 69.20 : x
  2. Step 2: Convert to fraction form
    78.47/108.49 = 69.20/x
  3. Step 3: Cross multiply
    78.47x = 108.49 × 69.20
  4. Step 4: Simplify right side
    78.47x = 7,507.94
  5. Step 5: Solve for x
    x = 7,507.94/78.47
  6. Step 6: Final answer
    x = 95.68

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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.