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Finding the Fourth Proportional to 121.87, 168.15 and 72.07

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Solution

The fourth proportional to 121.87, 168.15 and 72.07 is: 99.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.87 : 168.15 = 72.07 : x
  2. Step 2: Convert to fraction form
    121.87/168.15 = 72.07/x
  3. Step 3: Cross multiply
    121.87x = 168.15 × 72.07
  4. Step 4: Simplify right side
    121.87x = 12,118.57
  5. Step 5: Solve for x
    x = 12,118.57/121.87
  6. Step 6: Final answer
    x = 99.44

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.