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Finding the Fourth Proportional to 99.86, 149.64 and 72.80

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Solution

The fourth proportional to 99.86, 149.64 and 72.80 is: 109.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    99.86 : 149.64 = 72.80 : x
  2. Step 2: Convert to fraction form
    99.86/149.64 = 72.80/x
  3. Step 3: Cross multiply
    99.86x = 149.64 × 72.80
  4. Step 4: Simplify right side
    99.86x = 10,893.79
  5. Step 5: Solve for x
    x = 10,893.79/99.86
  6. Step 6: Final answer
    x = 109.09

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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.