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Finding the Fourth Proportional to 99.12, 148.50 and 81.90

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Solution

The fourth proportional to 99.12, 148.50 and 81.90 is: 122.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    99.12 : 148.50 = 81.90 : x
  2. Step 2: Convert to fraction form
    99.12/148.50 = 81.90/x
  3. Step 3: Cross multiply
    99.12x = 148.50 × 81.90
  4. Step 4: Simplify right side
    99.12x = 12,162.15
  5. Step 5: Solve for x
    x = 12,162.15/99.12
  6. Step 6: Final answer
    x = 122.70

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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.