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Finding the Fourth Proportional to 216.65, 324.78 and 79.61

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Solution

The fourth proportional to 216.65, 324.78 and 79.61 is: 119.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    216.65 : 324.78 = 79.61 : x
  2. Step 2: Convert to fraction form
    216.65/324.78 = 79.61/x
  3. Step 3: Cross multiply
    216.65x = 324.78 × 79.61
  4. Step 4: Simplify right side
    216.65x = 25,853.81
  5. Step 5: Solve for x
    x = 25,853.81/216.65
  6. Step 6: Final answer
    x = 119.33

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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.