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Finding the Fourth Proportional to 216.18, 298.38 and 128.86

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Solution

The fourth proportional to 216.18, 298.38 and 128.86 is: 177.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    216.18 : 298.38 = 128.86 : x
  2. Step 2: Convert to fraction form
    216.18/298.38 = 128.86/x
  3. Step 3: Cross multiply
    216.18x = 298.38 × 128.86
  4. Step 4: Simplify right side
    216.18x = 38,449.25
  5. Step 5: Solve for x
    x = 38,449.25/216.18
  6. Step 6: Final answer
    x = 177.86

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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.