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Finding the Fourth Proportional to 99.79, 149.67 and 72.90

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Solution

The fourth proportional to 99.79, 149.67 and 72.90 is: 109.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    99.79 : 149.67 = 72.90 : x
  2. Step 2: Convert to fraction form
    99.79/149.67 = 72.90/x
  3. Step 3: Cross multiply
    99.79x = 149.67 × 72.90
  4. Step 4: Simplify right side
    99.79x = 10,910.94
  5. Step 5: Solve for x
    x = 10,910.94/99.79
  6. Step 6: Final answer
    x = 109.34

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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.