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Finding the Fourth Proportional to 261.60, 391.12 and 221.48

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Solution

The fourth proportional to 261.60, 391.12 and 221.48 is: 331.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    261.60 : 391.12 = 221.48 : x
  2. Step 2: Convert to fraction form
    261.60/391.12 = 221.48/x
  3. Step 3: Cross multiply
    261.60x = 391.12 × 221.48
  4. Step 4: Simplify right side
    261.60x = 86,625.26
  5. Step 5: Solve for x
    x = 86,625.26/261.60
  6. Step 6: Final answer
    x = 331.14

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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.