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Finding the Fourth Proportional to 216.78, 299.10 and 129.45

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Solution

The fourth proportional to 216.78, 299.10 and 129.45 is: 178.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    216.78 : 299.10 = 129.45 : x
  2. Step 2: Convert to fraction form
    216.78/299.10 = 129.45/x
  3. Step 3: Cross multiply
    216.78x = 299.10 × 129.45
  4. Step 4: Simplify right side
    216.78x = 38,718.50
  5. Step 5: Solve for x
    x = 38,718.50/216.78
  6. Step 6: Final answer
    x = 178.61

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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.