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Finding the Fourth Proportional to 160.81, 221.96 and 128.21

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Solution

The fourth proportional to 160.81, 221.96 and 128.21 is: 176.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    160.81 : 221.96 = 128.21 : x
  2. Step 2: Convert to fraction form
    160.81/221.96 = 128.21/x
  3. Step 3: Cross multiply
    160.81x = 221.96 × 128.21
  4. Step 4: Simplify right side
    160.81x = 28,455.74
  5. Step 5: Solve for x
    x = 28,455.74/160.81
  6. Step 6: Final answer
    x = 176.96

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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.