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Finding the Fourth Proportional to 155.22, 214.11 and 128.88

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Solution

The fourth proportional to 155.22, 214.11 and 128.88 is: 177.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    155.22 : 214.11 = 128.88 : x
  2. Step 2: Convert to fraction form
    155.22/214.11 = 128.88/x
  3. Step 3: Cross multiply
    155.22x = 214.11 × 128.88
  4. Step 4: Simplify right side
    155.22x = 27,594.50
  5. Step 5: Solve for x
    x = 27,594.50/155.22
  6. Step 6: Final answer
    x = 177.78

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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.