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Finding the Fourth Proportional to 99.81, 149.78 and 54.17

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Solution

The fourth proportional to 99.81, 149.78 and 54.17 is: 81.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    99.81 : 149.78 = 54.17 : x
  2. Step 2: Convert to fraction form
    99.81/149.78 = 54.17/x
  3. Step 3: Cross multiply
    99.81x = 149.78 × 54.17
  4. Step 4: Simplify right side
    99.81x = 8,114.09
  5. Step 5: Solve for x
    x = 8,114.09/99.81
  6. Step 6: Final answer
    x = 81.29

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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.