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Finding the Fourth Proportional to 216.46, 298.78 and 129.20

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Solution

The fourth proportional to 216.46, 298.78 and 129.20 is: 178.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    216.46 : 298.78 = 129.20 : x
  2. Step 2: Convert to fraction form
    216.46/298.78 = 129.20/x
  3. Step 3: Cross multiply
    216.46x = 298.78 × 129.20
  4. Step 4: Simplify right side
    216.46x = 38,602.38
  5. Step 5: Solve for x
    x = 38,602.38/216.46
  6. Step 6: Final answer
    x = 178.33

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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.