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Finding the Fourth Proportional to 99.86, 149.78 and 31.39

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Solution

The fourth proportional to 99.86, 149.78 and 31.39 is: 47.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    99.86 : 149.78 = 31.39 : x
  2. Step 2: Convert to fraction form
    99.86/149.78 = 31.39/x
  3. Step 3: Cross multiply
    99.86x = 149.78 × 31.39
  4. Step 4: Simplify right side
    99.86x = 4,701.59
  5. Step 5: Solve for x
    x = 4,701.59/99.86
  6. Step 6: Final answer
    x = 47.08

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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.