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Finding the Fourth Proportional to 121.89, 168.01 and 90.76

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Solution

The fourth proportional to 121.89, 168.01 and 90.76 is: 125.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.89 : 168.01 = 90.76 : x
  2. Step 2: Convert to fraction form
    121.89/168.01 = 90.76/x
  3. Step 3: Cross multiply
    121.89x = 168.01 × 90.76
  4. Step 4: Simplify right side
    121.89x = 15,248.59
  5. Step 5: Solve for x
    x = 15,248.59/121.89
  6. Step 6: Final answer
    x = 125.10

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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.