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Finding the Fourth Proportional to 291.20, 402.15 and 221.25

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Solution

The fourth proportional to 291.20, 402.15 and 221.25 is: 305.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    291.20 : 402.15 = 221.25 : x
  2. Step 2: Convert to fraction form
    291.20/402.15 = 221.25/x
  3. Step 3: Cross multiply
    291.20x = 402.15 × 221.25
  4. Step 4: Simplify right side
    291.20x = 88,978.03
  5. Step 5: Solve for x
    x = 88,978.03/291.20
  6. Step 6: Final answer
    x = 305.56

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.