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Finding the Fourth Proportional to 321.72, 482.28 and 139.25

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Solution

The fourth proportional to 321.72, 482.28 and 139.25 is: 208.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    321.72 : 482.28 = 139.25 : x
  2. Step 2: Convert to fraction form
    321.72/482.28 = 139.25/x
  3. Step 3: Cross multiply
    321.72x = 482.28 × 139.25
  4. Step 4: Simplify right side
    321.72x = 67,155.08
  5. Step 5: Solve for x
    x = 67,155.08/321.72
  6. Step 6: Final answer
    x = 208.74

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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.