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Finding the Fourth Proportional to 221.54, 305.74 and 128.32

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Solution

The fourth proportional to 221.54, 305.74 and 128.32 is: 177.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    221.54 : 305.74 = 128.32 : x
  2. Step 2: Convert to fraction form
    221.54/305.74 = 128.32/x
  3. Step 3: Cross multiply
    221.54x = 305.74 × 128.32
  4. Step 4: Simplify right side
    221.54x = 39,232.56
  5. Step 5: Solve for x
    x = 39,232.56/221.54
  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.