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Finding the Fourth Proportional to 216.38, 324.66 and 86.47

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Solution

The fourth proportional to 216.38, 324.66 and 86.47 is: 129.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    216.38 : 324.66 = 86.47 : x
  2. Step 2: Convert to fraction form
    216.38/324.66 = 86.47/x
  3. Step 3: Cross multiply
    216.38x = 324.66 × 86.47
  4. Step 4: Simplify right side
    216.38x = 28,071.29
  5. Step 5: Solve for x
    x = 28,071.29/216.38
  6. Step 6: Final answer
    x = 129.73

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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.