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Finding the Fourth Proportional to 99.81, 149.72 and 54.15

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Solution

The fourth proportional to 99.81, 149.72 and 54.15 is: 81.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    99.81 : 149.72 = 54.15 : x
  2. Step 2: Convert to fraction form
    99.81/149.72 = 54.15/x
  3. Step 3: Cross multiply
    99.81x = 149.72 × 54.15
  4. Step 4: Simplify right side
    99.81x = 8,107.07
  5. Step 5: Solve for x
    x = 8,107.07/99.81
  6. Step 6: Final answer
    x = 81.23

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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.