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Finding the Fourth Proportional to 99.90, 149.04 and 81.81

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Solution

The fourth proportional to 99.90, 149.04 and 81.81 is: 122.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    99.90 : 149.04 = 81.81 : x
  2. Step 2: Convert to fraction form
    99.90/149.04 = 81.81/x
  3. Step 3: Cross multiply
    99.90x = 149.04 × 81.81
  4. Step 4: Simplify right side
    99.90x = 12,192.96
  5. Step 5: Solve for x
    x = 12,192.96/99.90
  6. Step 6: Final answer
    x = 122.05

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.