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Finding the Fourth Proportional to 216.54, 324.90 and 86.58

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Solution

The fourth proportional to 216.54, 324.90 and 86.58 is: 129.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    216.54 : 324.90 = 86.58 : x
  2. Step 2: Convert to fraction form
    216.54/324.90 = 86.58/x
  3. Step 3: Cross multiply
    216.54x = 324.90 × 86.58
  4. Step 4: Simplify right side
    216.54x = 28,129.84
  5. Step 5: Solve for x
    x = 28,129.84/216.54
  6. Step 6: Final answer
    x = 129.91

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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.