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Finding the Fourth Proportional to 137.76, 189.95 and 128.04

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Solution

The fourth proportional to 137.76, 189.95 and 128.04 is: 176.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    137.76 : 189.95 = 128.04 : x
  2. Step 2: Convert to fraction form
    137.76/189.95 = 128.04/x
  3. Step 3: Cross multiply
    137.76x = 189.95 × 128.04
  4. Step 4: Simplify right side
    137.76x = 24,321.20
  5. Step 5: Solve for x
    x = 24,321.20/137.76
  6. Step 6: Final answer
    x = 176.55

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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.