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Finding the Fourth Proportional to 99.89, 149.08 and 86.98

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Solution

The fourth proportional to 99.89, 149.08 and 86.98 is: 129.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    99.89 : 149.08 = 86.98 : x
  2. Step 2: Convert to fraction form
    99.89/149.08 = 86.98/x
  3. Step 3: Cross multiply
    99.89x = 149.08 × 86.98
  4. Step 4: Simplify right side
    99.89x = 12,966.98
  5. Step 5: Solve for x
    x = 12,966.98/99.89
  6. Step 6: Final answer
    x = 129.81

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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.