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Finding the Fourth Proportional to 78.54, 108.17 and 72.47

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Solution

The fourth proportional to 78.54, 108.17 and 72.47 is: 99.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.54 : 108.17 = 72.47 : x
  2. Step 2: Convert to fraction form
    78.54/108.17 = 72.47/x
  3. Step 3: Cross multiply
    78.54x = 108.17 × 72.47
  4. Step 4: Simplify right side
    78.54x = 7,838.18
  5. Step 5: Solve for x
    x = 7,838.18/78.54
  6. Step 6: Final answer
    x = 99.80

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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.