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Finding the Fourth Proportional to 159.15, 219.78 and 128.23

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Solution

The fourth proportional to 159.15, 219.78 and 128.23 is: 177.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    159.15 : 219.78 = 128.23 : x
  2. Step 2: Convert to fraction form
    159.15/219.78 = 128.23/x
  3. Step 3: Cross multiply
    159.15x = 219.78 × 128.23
  4. Step 4: Simplify right side
    159.15x = 28,183.08
  5. Step 5: Solve for x
    x = 28,183.08/159.15
  6. Step 6: Final answer
    x = 177.09

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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.