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Finding the Fourth Proportional to 152.20, 209.91 and 128.87

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Solution

The fourth proportional to 152.20, 209.91 and 128.87 is: 177.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    152.20 : 209.91 = 128.87 : x
  2. Step 2: Convert to fraction form
    152.20/209.91 = 128.87/x
  3. Step 3: Cross multiply
    152.20x = 209.91 × 128.87
  4. Step 4: Simplify right side
    152.20x = 27,049.64
  5. Step 5: Solve for x
    x = 27,049.64/152.20
  6. Step 6: Final answer
    x = 177.72

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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.