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Finding the Fourth Proportional to 216.61, 324.96 and 86.65

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Solution

The fourth proportional to 216.61, 324.96 and 86.65 is: 129.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    216.61 : 324.96 = 86.65 : x
  2. Step 2: Convert to fraction form
    216.61/324.96 = 86.65/x
  3. Step 3: Cross multiply
    216.61x = 324.96 × 86.65
  4. Step 4: Simplify right side
    216.61x = 28,157.78
  5. Step 5: Solve for x
    x = 28,157.78/216.61
  6. Step 6: Final answer
    x = 129.99

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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.