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Finding the Fourth Proportional to 221.28, 305.34 and 128.02

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Solution

The fourth proportional to 221.28, 305.34 and 128.02 is: 176.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    221.28 : 305.34 = 128.02 : x
  2. Step 2: Convert to fraction form
    221.28/305.34 = 128.02/x
  3. Step 3: Cross multiply
    221.28x = 305.34 × 128.02
  4. Step 4: Simplify right side
    221.28x = 39,089.63
  5. Step 5: Solve for x
    x = 39,089.63/221.28
  6. Step 6: Final answer
    x = 176.65

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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.