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Finding the Fourth Proportional to 137.58, 189.77 and 121.79

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Solution

The fourth proportional to 137.58, 189.77 and 121.79 is: 167.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    137.58 : 189.77 = 121.79 : x
  2. Step 2: Convert to fraction form
    137.58/189.77 = 121.79/x
  3. Step 3: Cross multiply
    137.58x = 189.77 × 121.79
  4. Step 4: Simplify right side
    137.58x = 23,110.53
  5. Step 5: Solve for x
    x = 23,110.53/137.58
  6. Step 6: Final answer
    x = 167.98

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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.