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Finding the Fourth Proportional to 216.80, 299.09 and 129.42

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Solution

The fourth proportional to 216.80, 299.09 and 129.42 is: 178.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    216.80 : 299.09 = 129.42 : x
  2. Step 2: Convert to fraction form
    216.80/299.09 = 129.42/x
  3. Step 3: Cross multiply
    216.80x = 299.09 × 129.42
  4. Step 4: Simplify right side
    216.80x = 38,708.23
  5. Step 5: Solve for x
    x = 38,708.23/216.80
  6. Step 6: Final answer
    x = 178.54

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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.