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Finding the Fourth Proportional to 137.84, 189.78 and 128.66

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Solution

The fourth proportional to 137.84, 189.78 and 128.66 is: 177.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    137.84 : 189.78 = 128.66 : x
  2. Step 2: Convert to fraction form
    137.84/189.78 = 128.66/x
  3. Step 3: Cross multiply
    137.84x = 189.78 × 128.66
  4. Step 4: Simplify right side
    137.84x = 24,417.09
  5. Step 5: Solve for x
    x = 24,417.09/137.84
  6. Step 6: Final answer
    x = 177.14

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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.