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Finding the Fourth Proportional to 321.57, 482.15 and 138.87

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Solution

The fourth proportional to 321.57, 482.15 and 138.87 is: 208.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    321.57 : 482.15 = 138.87 : x
  2. Step 2: Convert to fraction form
    321.57/482.15 = 138.87/x
  3. Step 3: Cross multiply
    321.57x = 482.15 × 138.87
  4. Step 4: Simplify right side
    321.57x = 66,955.48
  5. Step 5: Solve for x
    x = 66,955.48/321.57
  6. Step 6: Final answer
    x = 208.21

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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.