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Finding the Fourth Proportional to 99.17, 136.85 and 78.41

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Solution

The fourth proportional to 99.17, 136.85 and 78.41 is: 108.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    99.17 : 136.85 = 78.41 : x
  2. Step 2: Convert to fraction form
    99.17/136.85 = 78.41/x
  3. Step 3: Cross multiply
    99.17x = 136.85 × 78.41
  4. Step 4: Simplify right side
    99.17x = 10,730.41
  5. Step 5: Solve for x
    x = 10,730.41/99.17
  6. Step 6: Final answer
    x = 108.20

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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.