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Finding the Fourth Proportional to 216.34, 324.20 and 139.28

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Solution

The fourth proportional to 216.34, 324.20 and 139.28 is: 208.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    216.34 : 324.20 = 139.28 : x
  2. Step 2: Convert to fraction form
    216.34/324.20 = 139.28/x
  3. Step 3: Cross multiply
    216.34x = 324.20 × 139.28
  4. Step 4: Simplify right side
    216.34x = 45,154.58
  5. Step 5: Solve for x
    x = 45,154.58/216.34
  6. Step 6: Final answer
    x = 208.72

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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.