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Finding the Fourth Proportional to 216.81, 324.90 and 79.71

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Solution

The fourth proportional to 216.81, 324.90 and 79.71 is: 119.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    216.81 : 324.90 = 79.71 : x
  2. Step 2: Convert to fraction form
    216.81/324.90 = 79.71/x
  3. Step 3: Cross multiply
    216.81x = 324.90 × 79.71
  4. Step 4: Simplify right side
    216.81x = 25,897.78
  5. Step 5: Solve for x
    x = 25,897.78/216.81
  6. Step 6: Final answer
    x = 119.45

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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.