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Finding the Fourth Proportional to 216.78, 325.29 and 139.74

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Solution

The fourth proportional to 216.78, 325.29 and 139.74 is: 209.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    216.78 : 325.29 = 139.74 : x
  2. Step 2: Convert to fraction form
    216.78/325.29 = 139.74/x
  3. Step 3: Cross multiply
    216.78x = 325.29 × 139.74
  4. Step 4: Simplify right side
    216.78x = 45,456.02
  5. Step 5: Solve for x
    x = 45,456.02/216.78
  6. Step 6: Final answer
    x = 209.69

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.