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Finding the Fourth Proportional to 221.31, 305.36 and 128.03

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Solution

The fourth proportional to 221.31, 305.36 and 128.03 is: 176.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    221.31 : 305.36 = 128.03 : x
  2. Step 2: Convert to fraction form
    221.31/305.36 = 128.03/x
  3. Step 3: Cross multiply
    221.31x = 305.36 × 128.03
  4. Step 4: Simplify right side
    221.31x = 39,096.32
  5. Step 5: Solve for x
    x = 39,096.32/221.31
  6. Step 6: Final answer
    x = 176.66

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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.