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Finding the Fourth Proportional to 321.28, 482.14 and 138.70

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Solution

The fourth proportional to 321.28, 482.14 and 138.70 is: 208.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    321.28 : 482.14 = 138.70 : x
  2. Step 2: Convert to fraction form
    321.28/482.14 = 138.70/x
  3. Step 3: Cross multiply
    321.28x = 482.14 × 138.70
  4. Step 4: Simplify right side
    321.28x = 66,870.88
  5. Step 5: Solve for x
    x = 66,870.88/321.28
  6. Step 6: Final answer
    x = 208.14

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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.