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Finding the Fourth Proportional to 221.48, 305.58 and 128.22

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Solution

The fourth proportional to 221.48, 305.58 and 128.22 is: 176.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    221.48 : 305.58 = 128.22 : x
  2. Step 2: Convert to fraction form
    221.48/305.58 = 128.22/x
  3. Step 3: Cross multiply
    221.48x = 305.58 × 128.22
  4. Step 4: Simplify right side
    221.48x = 39,181.02
  5. Step 5: Solve for x
    x = 39,181.02/221.48
  6. Step 6: Final answer
    x = 176.91

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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.