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Finding the Fourth Proportional to 99.90, 149.87 and 31.42

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Solution

The fourth proportional to 99.90, 149.87 and 31.42 is: 47.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    99.90 : 149.87 = 31.42 : x
  2. Step 2: Convert to fraction form
    99.90/149.87 = 31.42/x
  3. Step 3: Cross multiply
    99.90x = 149.87 × 31.42
  4. Step 4: Simplify right side
    99.90x = 4,708.92
  5. Step 5: Solve for x
    x = 4,708.92/99.90
  6. Step 6: Final answer
    x = 47.14

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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.