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Finding the Fourth Proportional to 137.76, 189.90 and 121.56

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Solution

The fourth proportional to 137.76, 189.90 and 121.56 is: 167.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    137.76 : 189.90 = 121.56 : x
  2. Step 2: Convert to fraction form
    137.76/189.90 = 121.56/x
  3. Step 3: Cross multiply
    137.76x = 189.90 × 121.56
  4. Step 4: Simplify right side
    137.76x = 23,084.24
  5. Step 5: Solve for x
    x = 23,084.24/137.76
  6. Step 6: Final answer
    x = 167.57

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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.