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Finding the Fourth Proportional to 161.32, 221.88 and 128.20

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Solution

The fourth proportional to 161.32, 221.88 and 128.20 is: 176.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    161.32 : 221.88 = 128.20 : x
  2. Step 2: Convert to fraction form
    161.32/221.88 = 128.20/x
  3. Step 3: Cross multiply
    161.32x = 221.88 × 128.20
  4. Step 4: Simplify right side
    161.32x = 28,445.02
  5. Step 5: Solve for x
    x = 28,445.02/161.32
  6. Step 6: Final answer
    x = 176.33

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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.