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Finding the Fourth Proportional to 216.26, 298.21 and 128.91

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Solution

The fourth proportional to 216.26, 298.21 and 128.91 is: 177.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    216.26 : 298.21 = 128.91 : x
  2. Step 2: Convert to fraction form
    216.26/298.21 = 128.91/x
  3. Step 3: Cross multiply
    216.26x = 298.21 × 128.91
  4. Step 4: Simplify right side
    216.26x = 38,442.25
  5. Step 5: Solve for x
    x = 38,442.25/216.26
  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.