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Finding the Fourth Proportional to 211.62, 291.96 and 128.74

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Solution

The fourth proportional to 211.62, 291.96 and 128.74 is: 177.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    211.62 : 291.96 = 128.74 : x
  2. Step 2: Convert to fraction form
    211.62/291.96 = 128.74/x
  3. Step 3: Cross multiply
    211.62x = 291.96 × 128.74
  4. Step 4: Simplify right side
    211.62x = 37,586.93
  5. Step 5: Solve for x
    x = 37,586.93/211.62
  6. Step 6: Final answer
    x = 177.62

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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.