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Finding the Fourth Proportional to 211.74, 292.12 and 128.85

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Solution

The fourth proportional to 211.74, 292.12 and 128.85 is: 177.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    211.74 : 292.12 = 128.85 : x
  2. Step 2: Convert to fraction form
    211.74/292.12 = 128.85/x
  3. Step 3: Cross multiply
    211.74x = 292.12 × 128.85
  4. Step 4: Simplify right side
    211.74x = 37,639.66
  5. Step 5: Solve for x
    x = 37,639.66/211.74
  6. Step 6: Final answer
    x = 177.76

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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.